A model for compensation of radial shift was established to further improve fabrication precision during polar laser direct writing. At first, exposure dose distribution model of polar laser direct writing was established , and the cause of radial shift was analyzed. And then, the linewidth broadening model and radial shift model were established corresponding to object lens with numerical aperture 0.5, and the coupling relationship between linewidth broadening and radial shift was analyzed. Based on the above mentioned, compensation models of linewidth broadening and radial shift were established. Simulation results indicate that the radial drift value was about 3 times linewidth broadening value. The compensation of radial shift reduces the system error of polar laser direct writing and improves the fabrication precision.