Based on the microscopic phase-field dynamic diffusion equation (the Langevin equation), the effects of concentration and temperature on the antisite defect evolution in Al3Li phase are investigated. The results show that the main antisite defect in Al3Li phase is AlLi, in which the Li sites are taken by Al atoms; there also exists a little amount of LiAl, in which the Al sites are taken by Li atoms. The two antisite defects are all increase with the increase of temperature, and the rising rate for AlLi is far larger than for LiAl. With the increase of Li concentration, the AlLi concentration decreases slowly and the LiAl concentration increases slightly, but still far less than the AlLi concentration . It is found that the effects of temperature on the antisite defects are more obvious than the concentration.