The tension clamp of transmission line transmits the load of the ground wire to the tower, which is the key bearing part of the line and generally processed by crimping technology. In the process of engineering operation, the failure of the crimp type tensioning clamp often occurs due to the crimp defect, resulting in serious accidents. In this paper, the grip force experiments of NY400/35 type wire clip with normal crimping and crimping defects are carried out. The failure process and force transmission characteristics of wire clip are studied by using displacement and strain experimental data. The results showed that steel core and aluminum tube in the wire clip are subjected to wire tension simultaneously, and the wire clip is subjected to load: There are two paths for force transmission, one is steel anchor-aluminum tube-wire aluminum strand, the other is steel anchor-wire steel core; Insufficient threading length will lead to reduced contact area between steel core and steel anchor threading tube and reduced grip force, resulting in steel core pulling out of steel anchor threading tube, thus reducing grip force of tension-resistant clamp. When there is insufficient pipe length defect, the load of aluminum tube will increase by about 44.5%; When the pipe length is greater than 50 mm, the grip strength of the strain clamp can meet the specification requirements.