In the composite material single lap joint structure, due to the eccentricity of the load, the lateral force is generated in the lap joint, which causes the lateral displacement of the joint and deflects the bolt.The stress distribution of bolt and nut under static load is analyzed in this paper. Results show that eccentric moment in the single lap produces a strong stress in the thread position of the bolt, resulting in the fracture failure of the bolt. And a strong circumferential stress raiseing in the nut, causing the nut to break.The lateral constraints on the laminated plates can effectively reduce the stress amplitude in the bolts and nuts.The calculated results agree with the test failure mode.