Abstract: In order to solve the contradiction between the depth of field and the resolution of traditional microscope objective, the wavefront coding(WFC) 10× microscope objective was designed and researched based on WFC technique. Combining with traditional optical design software, an optimization method for cubic phase mask parameters based on modulation transfer function (MTF) consistency was used to achieve the point spread function(PSF) consistency of the system within a certain range near the image plane. In addition, a 10× microscope objective lens with an extended cubic phase mask was also designed to compare the effect of the depth-of-focus expansion using two different phase mask systems.Design results show that the cubic phase mask has a good focal depth expansion effect, which can extend the focal depth of the traditional 10× microscope objective by 15 times. Simulation and experimental results indicate that the encoded images of system are sharp within ±15 times depth of focus distance after filtering so as to extend the field depth of system.