The invention discloses a calculation method of a bolt elastic interaction coefficient method. The method is based on the elastic interaction coefficient method, and a novel mathematical model for researching the bolt connection elastic interaction on a bolt flange with a sealing gasket is provided. The method takes a finite element analysis software ANSYS and a calculation software MATLAB as thetools, calculates the elastic interaction coefficient between the bolts, under the condition that the target pre-tightening force of the bolts is determined, calculates the initial pre-tightening force of all the bolts on the bolt flange, so that the final pre-tightening force of the bolts is more uniform. According to the method, an analysis model for simulating the elastic interaction behavior of the bolts and the flanges is established, and the finite element analysis verification is carried out. The initial pre-tightening force of each bolt on the bolt flange is optimized on the basis of traditional sequential tightening. Under the condition that the implementation difficulty is not increased, the final bolt pre-tightening force and the target bolt pre-tightening force are reduced from47% of the maximum difference value to 7% of the maximum difference value.