The combined connection with welds and bolds can be widely used in reinforcing the joint in steel structure. In this paper, proposed design method of combined connection with bolts and longitudinal welds was given based on the tests and finite element analysis (FEA). The method considers the effect of the strength ratio between bolts and welds. The safety and reliability of the method were verified by FEA and comparison with other design method. The design method can contribute to the promotion of the application of the combined connections.