| Based on vehicle track coupling dynamics and wheel rail rolling contact analysis, a rail wear prediction model was developed combining the material wear theory and the corresponding calculating program was written, which can quantitatively predict the distribution and development of rail wear. In view of the significant effect of discrete grid density of wheel rail contact patch on the prediction model, the influencing mechanism of the factor was analyzed from the perspectives of contact force distribution, wear distribution and so on. The reasonable grid density of contact patch was discussed. The research results show that the grid density does not affect the correctness of calculated results, but sparse grid causes many sharp shape changes in the creeping force and wear distributions. Increasing the grid density can improve the precision and smoothness of wear distribution, but the computation cost increases dramatically. When the grid density increases to 20×20, the change of rail wear rate tends to be stable. Continuing increasing the density does not bring about obvious improvement. Therefore, a grid density of 20×20 is suggested in the prediction model, which can achieve a high computation efficiency and accuracy.