The accurate placement of the ball head fixed to the aircraft structure into the ball socket at the end of numerical control locator is a prerequisite for attitude adjustment and docking of the aircraft structure. Aiming at the problem of locating large components accurately, a sliding mode control based ball adaptive positioning method was proposed. Firstly, perform amplitude limiting and FIR filtering on the output of the three-dimensional force sensor, and perform zero crossing linear regression on its calibration curve to improve the measurement accuracy of the force sensor; Secondly, a force guided locator driving model is constructed, and a force controller is designed based on sliding mode theory, of which design rationality is verified based on Lyapunov stability criteria; Then, a ball head dimming model based on sliding mode control is built in Simulink environment, and the simulation results show that the designed force feedback control system has no vibration and fast response speed; Finally, a simulation part of the fuselage is tested to verify that the test results meet the designed requirement of ball head low stress placement, which verifies the effectiveness of the method.