There is geometric distortion of image in integral Stereolithography (SL) system, and the geometric distortion will influence the building accuracy of the SL system. To improve the building accuracy of the SL system, researches of distortion correction of image in the SL system are carried out. The distortion model of binary cubic polynomial interpolation is established with least-square method. The gray scale rebuilding is implemented with space-variable linear interpolation by using VC++6.0. The experimental results indicate that the geometric distortion of the image in integral SL system has been eliminated remarkably, and the radial RMS error is 0.96 pixels. The research lays a foundation for improving building accuracy of the integral SL System.