Considering that the large aperture primary mirror of space optical remote sensor should have light weight and high surface quality,we designed an ultra-lightweight silicon carbide mirror.Firstly,the lightweight structure of the mirror was defined.Then,based on integrated optimization method,ISight software was used for implementing such design processes as geometric modeling,finite element analysis and surface fitting,and automatic operation was realized.The structure parameters of the mirror were all optimization variables,and both the mass and the RMS surface figure error of the mirror were taken as objective functions.The multi-objective,global optimization was achieved by using Non-dominated Sorting Genetic Algorithm II (NSGA-II).Finally,the optimal design was modified considering cast constraints and a verification model was constructed to evaluate the optimal design.The mass of the optimal mirror is 11.4 kg and the surface density is 37 kg/m2.Under the load of gravity vertical to the optical axis,the RMS surface figure error is 1 nm,and the first natural frequency reaches 1100 Hz.The result demonstrates the availability of the proposed approach.