Abstract: To solve the key problem of curing deformation of composite materials radar cover skin, curing process in near-spherical composite materials was simulated and investigated with the finite element method. Synthesizing simulation and test results show that the trend of deformation of mold and composites are almost the same, deformation increase gradually from centre to edge, mold has less influence on the deformation compared with the internal stress, and irreversible warping deformation resulting from the latter is the main factor on prototyping manufacturing precision of composites.