In order to insure the influence of crimping dimension on the locking properties of titanium alloy selflocking nut, the locking properties at different crimping dimension were detected by the machine in this paper, and the regularity between crimping dimension and locking properties was gained simultaneously. The results show that the selflocking torque and breakaway torque increase at beginning and then decrease with the increasing of frequency. The variant region was smaller at the 0.05mm and 0.10mm crimping dimension, and that at 0.15mm crimping dimension was biggest. The linear relationship appears between seating torque and preload, and the smaller crimping dimension is, the bigger slope of the linear is. The wrenching-stretching coefficient is 0.09, 0.12 and 0.16 at the crimping dimension of 0.05mm, 0.10mm and 0.15mm, respectively.