This paper proposes a method for matching next-to-leading order (NLO) QCD calculations with parton shower Monte Carlo (MC) simulations. The method ensures fully exclusive events with hadronization according to the MC model, accurate NLO total rates, and NLO results for distributions upon expansion in αs. Hard emissions are treated as in NLO, while soft/collinear emissions are handled by the MC with the same logarithmic accuracy. The method avoids double counting and allows unweighting with reasonable efficiency. A toy model is used to illustrate the method, and it is applied to W⁺W⁻ production in hadronic collisions. The method is clarified using a simplified toy model and demonstrated for W⁺W⁻ production. The approach combines NLO matrix elements with parton showers, ensuring smooth matching between hard and soft/collinear emission regions. The method is implemented in a QCD MC@NLO, which can generate events with NLO accuracy and handle both exclusive and inclusive observables. The results show that the MC@NLO method reduces numerical dependence on subleading logarithms and provides accurate predictions for both exclusive and inclusive observables. The method is validated using a toy model and applied to W⁺W⁻ production, demonstrating its effectiveness in combining NLO calculations with parton showers.This paper proposes a method for matching next-to-leading order (NLO) QCD calculations with parton shower Monte Carlo (MC) simulations. The method ensures fully exclusive events with hadronization according to the MC model, accurate NLO total rates, and NLO results for distributions upon expansion in αs. Hard emissions are treated as in NLO, while soft/collinear emissions are handled by the MC with the same logarithmic accuracy. The method avoids double counting and allows unweighting with reasonable efficiency. A toy model is used to illustrate the method, and it is applied to W⁺W⁻ production in hadronic collisions. The method is clarified using a simplified toy model and demonstrated for W⁺W⁻ production. The approach combines NLO matrix elements with parton showers, ensuring smooth matching between hard and soft/collinear emission regions. The method is implemented in a QCD MC@NLO, which can generate events with NLO accuracy and handle both exclusive and inclusive observables. The results show that the MC@NLO method reduces numerical dependence on subleading logarithms and provides accurate predictions for both exclusive and inclusive observables. The method is validated using a toy model and applied to W⁺W⁻ production, demonstrating its effectiveness in combining NLO calculations with parton showers.