Percutaneous mechanical thrombectomy (PMT) is an efficient way to treat the deep vein thrombosis (DVT). During the course of treatment, blood cell will be destroyed by the component of thrombectomy device, causing hemolysis. In this research, the computational fluid dynamics (CFD) methodology is used to investigate hemolysis effect of rotary cutting thrombectomy device. And a prototype of rotary cutting thrombectomy device is made to carry out two corresponding experiments to verify the simulation results. CFD results indicate that the hemolysis rate increases significantly with the rise of rotation speed of cutting component. The experimental results are in good consistence with the CFD results, and shows that the longer the working time, the higher the hemolysis rate. Thus a rotation speed between 5,000 rpm and 10,000 rpm can be considered reasonable. The results can be served as a helpful guidance for the design of such thrombectomy devices.