It is quite difficult to solve the problem of mixing friction in mechanical seal has relation to coupling function on more physical quantities between spring deformation and elastic hydrodynamic lubrication. And no available business software can directly work it out, so the C language programming was used to calculate. Allowing for micropolar fluids effect, dynamics and mathematical models on mixing friction in mechanical seal were established, and the problems for the distributions of fluid film pressure in film lubrication under the different micropolar fluids parameters were solved by using finite difference method, then the solutions of pressure and spillage value were obtained. The results show that raising of micropolar fluids parameters such as coupling coefficient and characteristic length makes fluid film pressure increase, and then pressure drops and spillage decreases, which keeps seal reliability.