The support structure based on kinematic principle had been wildly used in the axial support on large-diameter telescope. But it is not maturely applied in the lateral support system. A lateral support structure based on kinematic principle is explained. Based on a primary mirror with a diameter of 2.04 m, a support structure with more details was designed and analyzed by the ANSYS Parametric Design Language. Selected the Root Mean Square (RMS) of the primary mirror when the optical axis was vertical as the objective function, the support reaction was optimized by the simulated annealing algorithm. Final surface error RMS was 16.67 nm. Surface error with different obliquities were calculated, which meets the requirement that the RMS should be less than λ/3.