In order to maintain the surface accuracy of the tilt mirror for space image stabilization system,the lightweight design of tilt mirror was realized. The topology optimization method was introduced into the design of a  110 mm round mirror. The support part of the mirror was designed by the method. Meanwhile,the theory and the method of topology optimization were introduced in detail. Through the thoughts of SIMP (Solid Isotropic Material with Penalization) and RAMP (Rational Approximation of Material Properties),ASMP (Adjusted Solid Material with Penalization) was proposed and its advantage was introduced. And simulations were done for various interpolation algorithms respectively. The results show that topology optimization result of ASMP interpolation algorithm is correct and reliable,and it is proved to be superior to the other interpolation algorithms. Meanwhile,topology optimization was done for the tilt mirror. The new topology optimization algorithm can improve the surface accuracy in a greater degree,and it is more flexible. The proposal interpolation algorithm can consummate traditional topology optimization interpolation algorithm,and it lays a solid foundation for the next parameter optimization.