The overall structure of the ultra precision hydrostatic guideway platform was designed with optimization by using the multi-output comprehensive evaluation method and the orthogonal experimental design. Finite Element Analysis (FEA) software was used to the orthogonal experiments and the comprehensive evaluation method was used in integration to evaluate the results in fuzzy math. By extreme difference analysis of comprehensive evaluation, the key and the non-critical factors affecting the deformation of the guideway were confirmed, therefore an optimization math model was developed for the structure design of the guideway platform. According to the optimization results, a novel and more rational design scheme was presented for the hydrostatic guideway platform. This design not only contributes to reducing the guideways deformations and improving the parallelism precision of the guideway, but also helps to reduce the mass of the whole platform with very good effects.