In order to achieve high assembly accuracy on the basis of low manufacturing accuracy and low cost, a method of deviation factor matching and optimization based on Taguchi theory is proposed. Firstly, the specific process of multi factor matching and optimization is given based on Taguchi theory. Secondly, the orthogonal experiments were set from the aspects of performance index, influencing factors determination, orthogonal table selection and so on, and the best level combination of each deviation was selected to form the factor matching and optimization experiment scheme based on Taguchi method. Finally, taking the horizontal machining center as the object, the Taguchi method is used to match the deviation factors of each mating surface, and the best parameter combination of control factors is A1B2C2D1E1, which verifies the effectiveness and practicability of Taguchi method. The research method in this study provides a strong support for the realization of high assembly accuracy and performance without increasing cost.