In order to optimize the traditional star tightening method,a flange joint tightening method based on the elastic interaction coefficient method was proposed.The optimized tightening method was simulated with finite element method,the tightening effect,i.e.bolt load size and uniformity,was analyzed,and the validity of the finite element simulation results and the feasibility of the proposed tightening method were verified by experiments.The results show that the optimized tightening method can pretighten the bolt load to more than 90% of the target load by one round of tightening,indicating the tightening effect is better than that of the traditional tightening method with six rounds of tightening.〖JP2〗The tightening method is suitable for different target loads.The results of the flange tightening experiment are in agreement with the simulation results,indicating the effectiveness of the simulation results and the feasibility of the proposed tightening method.