The invention relates to a bolt design method. The method comprises the following steps that 1, stress analysis is conducted on the bolt structure position by means of CAE, and load needed by axial acting force, shearing acting force and the sealing function is determined; 2, the bolt specification is selected according to the experienced diameter-length ratio, a proper bolt head is selected through the type of the supporting surface of a bolt; 3, the friction coefficient range of the bolt is designed, and an assembly preload target value is calculated; 4, the bolt strength grade and the tightening strategy are determined according to the preload target value; 5, the proper bolt specification and the tightening strategy are determined finally. Accordingly, calculation is conducted according to the friction coefficient of the specific bolt, that is to say, the actual production condition, bolt type selection, security coefficient setting, tolerance analysis and bolt tightening specification establishing are achieved, and the method is applicable to a torque method, a corner method and a yield point method of the bolt.