Accurate measurement of contact force is the foundation and prerequisite for achieving active compliant assembly of components, this article proposes an assembly contact force measurement method of large components based on distributed 3D force sensors for the precise and compliant control requirements of redundant drive parallel mechanisms. First, the kinematic model of assembly positioning mechanisms is Built, and an assembly contact force calculation method based on dynamic model is proposed. Subsequently, aiming at the problem of gravity compensation during the compliant assembly process of components, a centroid self-calibration method of the terminal based on multi attitude is proposed, and the centroid parameter is solved using the least squares method. Then, numerical simulation methods are used to analyze the measurement errors and installation angle errors of the sensor, as well as the influence of the centroid calibration strategy on the measurement error of assembly contact force. Finally, dynamic assembly contact force measurement experiments of large components are conducted in the laboratory. The experimental results show that compare with the six-dimensional force sensor, the assembly contact force standard deviation measured by distributed three-dimensional force sensors is reduced by 41.6%, and the assembly contact torque standard deviation is reduced by 47.1%.