Bolted connection is an important connection mode in engineering structures.The layout optimization of bolted connection structure can improve its mechanical performance.The finite element parameterized model of the bolted connection structure was established.The finite element mechanical analyses of the connection plates and bolts were carried out.The firefly algorithm was applied to optimize the bolt layout.The reasonable bolt layout was obtained.The maximum stress around the bolt hole was reduced.When the number of the bolts was 4,compared with the initial design,the optimized bolt layout is more reasonable and the maximum stress around the hole decreased to a great degree.When the number of the bolts was 6,the initial design schemes with three rows and two rows bolts were optimized.The optimized layout of the two cases was the same as the bolt layout with two rows.Numerical examples demonstrate the effectiveness of the firefly algorithm to solve the problem of bolt layout design. The research results can be used as reference for mechanical design.