A Zernike modal wavefront calculation method based on Computer Unified Device Architecture(CUDA) was presented for liquid crystal adaptive optical systems under the GPU general architecture.The wavefront calculation method was introduced and the CUDA characteristics were given.Then, a programming model for wavefront calculation by CUDA was established, in which it involved three kinds of optimized schemes including maximum threads, higher memory and transfer bandwidth.The method based on CUDA was tested and compared with the traditional method using CPU, and result shows that the consumed time by proposed method is less than 1 ms for a Zernike polynomial with 35 wavefromt values in resolution of 512×512, which means that GPU provides a computational power tens times greater than that of usual CPU-FPU combination.The method has reduced the system delay and improved correction speed and its optimized ideas for programming model can provide a reference for other computer models.