In the numerical simulation of light propagation along an inhomogeneous turbulent path, five methods for the selection of C2n between phase screens are discussed, to reduce the error due to the assumption that turbulence between phase screens is homogeneous. By calculating Rytov index and Fried parameter of plane wave and spherical wave, relative errors between simulative and theoretical results of the five methods are compared. It is found that setting C2n as the average refractive index structure constant of turbulence between phase screens can obtain the highest precision. And when the equivalent Rytov index-interval phase screen method is used to locate phase screens, choosing C2n as the average value of refractive index structure constants at the positions of two phase screens is also feasible.