CalcHEP 3.4 is a software package designed for the efficient evaluation and simulation of high energy physics collider processes at the parton level. It offers key features such as Feynman diagram computation, multi-particle phase space integration, and parton level event simulation. The software provides an easy-to-use graphical user interface (GUI), allows users to modify or introduce new models, and supports cross-checking results in different gauges. It also includes a batch interface for complex calculations involving many particles in the final state. CalcHEP can perform calculations from a theoretical model in the form of a Lagrangian down to phenomenology in the form of cross sections, parton level event simulation, and various kinematical distributions. The new features of CalcHEP 3.4 enhance its capabilities as an effective tool for modern collider phenomenology. CalcHEP consists of two modules: a symbolic and a numerical module. The symbolic module allows dynamic work with a physics model, symbolic calculation of squared matrix elements, and export of results as C-code. The numerical module evaluates phase space integrals to determine cross sections or decay widths and can histogram events to produce kinematical distributions. It can also be run in non-interactive mode using scripts, including a batch interface that automates production and decay processes and combines results to produce a final event file in Les Houches Event (LHE) format. CalcHEP supports a variety of models beyond the Standard Model (BSM), including SUSY models, Leptoquarks, Little Higgs, TechniColor, and others. It can be used as a matrix element generator for external programs and has interfaces with external programs like Isajet, SuSpect, and SPheno for spectra calculations. It also supports the generation of CalcHEP format model files using external tools like LanHEP, FeynRules, and SARAH. CalcHEP is designed to run on various UNIX platforms and includes a comprehensive set of parton distribution functions and tools for updating them. It supports the use of LHAPDF parton distribution functions and allows users to define their own kinematical functions and cuts. The software also includes tools for Monte Carlo integration, event generation, and distribution analysis. It can generate event files in LHE format and supports event mixing to combine different channels in one event file. CalcHEP is a powerful tool for collider physics studies, offering a wide range of features for both symbolic and numerical calculations.CalcHEP 3.4 is a software package designed for the efficient evaluation and simulation of high energy physics collider processes at the parton level. It offers key features such as Feynman diagram computation, multi-particle phase space integration, and parton level event simulation. The software provides an easy-to-use graphical user interface (GUI), allows users to modify or introduce new models, and supports cross-checking results in different gauges. It also includes a batch interface for complex calculations involving many particles in the final state. CalcHEP can perform calculations from a theoretical model in the form of a Lagrangian down to phenomenology in the form of cross sections, parton level event simulation, and various kinematical distributions. The new features of CalcHEP 3.4 enhance its capabilities as an effective tool for modern collider phenomenology. CalcHEP consists of two modules: a symbolic and a numerical module. The symbolic module allows dynamic work with a physics model, symbolic calculation of squared matrix elements, and export of results as C-code. The numerical module evaluates phase space integrals to determine cross sections or decay widths and can histogram events to produce kinematical distributions. It can also be run in non-interactive mode using scripts, including a batch interface that automates production and decay processes and combines results to produce a final event file in Les Houches Event (LHE) format. CalcHEP supports a variety of models beyond the Standard Model (BSM), including SUSY models, Leptoquarks, Little Higgs, TechniColor, and others. It can be used as a matrix element generator for external programs and has interfaces with external programs like Isajet, SuSpect, and SPheno for spectra calculations. It also supports the generation of CalcHEP format model files using external tools like LanHEP, FeynRules, and SARAH. CalcHEP is designed to run on various UNIX platforms and includes a comprehensive set of parton distribution functions and tools for updating them. It supports the use of LHAPDF parton distribution functions and allows users to define their own kinematical functions and cuts. The software also includes tools for Monte Carlo integration, event generation, and distribution analysis. It can generate event files in LHE format and supports event mixing to combine different channels in one event file. CalcHEP is a powerful tool for collider physics studies, offering a wide range of features for both symbolic and numerical calculations.