A small cone angle double cone pin synchronous locking mechanism has been designed for in orbit lifting locking and high stiffness load-bearing of the solar cell wing in the Mengtian Lab Module. The locking, load-bearing, and performance reliability of the lifting locking mechanism are guaranteed from the aspects of shaft rotation repeatability, driving characteristics, structural strength (stiffness), pin motion state, self-locking characteristics, and cone penetration depth repeatability control. The experimental results of the identified and finalized products show that the mechanism has a rotation repeatability accuracy of 0.0026°, a cone pin locking depth repeatability of better than 0.15 mm at high and low temperatures, and a locking stiffness of 1.07 × 105 Nm/rad, which meets the high-precision and high stiffness locking requirements of the solar cell wing in the Mengtian Lab Module.