The paper investigates the production of axion dark matter from cosmic strings in the post-inflationary scenario through lattice simulations. The authors confirm the logarithmic growth in the number of strings per Hubble patch and the spectral index of the power law scaling for the axion spectrum, which are observed in recent simulations. They compare two different initial random field configurations—fat-string type and thermal phase transition—and discuss the correlation between the axion spectrum and string evolution under different initial conditions. The impact of various parameters, such as the power law of the axion spectrum, nonlinearities around the QCD scale, and average inter-string distances, on the axion abundance is explored. A novel tetrahedralization-based string identification method is introduced, which ensures the connectedness of strings and provides a convenient way to assign the core location. The paper also derives a lower bound on the axion mass. The results support the insensitivity of scaling behaviors to different initial data and provide insights into the scaling regime and the cosmological evolution of the string network.The paper investigates the production of axion dark matter from cosmic strings in the post-inflationary scenario through lattice simulations. The authors confirm the logarithmic growth in the number of strings per Hubble patch and the spectral index of the power law scaling for the axion spectrum, which are observed in recent simulations. They compare two different initial random field configurations—fat-string type and thermal phase transition—and discuss the correlation between the axion spectrum and string evolution under different initial conditions. The impact of various parameters, such as the power law of the axion spectrum, nonlinearities around the QCD scale, and average inter-string distances, on the axion abundance is explored. A novel tetrahedralization-based string identification method is introduced, which ensures the connectedness of strings and provides a convenient way to assign the core location. The paper also derives a lower bound on the axion mass. The results support the insensitivity of scaling behaviors to different initial data and provide insights into the scaling regime and the cosmological evolution of the string network.