Abstract: The effects of cap size on residual geoid are analyzed for different order of VK and FEO kernels using Sandwell's gravity anomaly along the offshore of China Sea based on remove compute and recovery technology.The results demonstrate that the spherical cap radius increases had no significant influence on the residual geoid if a higher order of the kernel functionswas applied in our test region,for example,P=L=90 or P=L=120.From this study,a cap size of 3° is an optimal parameter when the results from the low or high order of kernel are compared and analyzed.The verification of geoid using GPS/Leveling data showed that the modified kernels could improve the precision with 1.5 cm in contrast with the results from spherical Stokes kernel.