The growing field of optical interferometry requires instruments with higher lateral resolution. High-resolution implies long processing time, which significantly affects testing efficiency. In order to improve the testing efficiency, a Zernike polynomial absolute flatness testing utilizing parallel acceleration of CPU/GPU heterogeneous computing was proposed, which used CPU for process to control and GPU multi-core advantage to discretize the elements in the flatness for parallel solving. Performance was further optimized useing mixed-precision in Zernike coefficient solving and peak-to-valley (PV) and root mean square (RMS) were solved with warp-level primitive instructions. Using 512×512, 1024×1024, 2 048×2 048, and 4096 ×4096 optically flat surfaces on the RTX3070–Laptop hardware, the speed increased by 47, 56, 58, and 70 times respectively in the overall process compared to the CPU version.