The work aims to improve the working efficiency of truss manipulators in sorting and palletizing off-line finished goods in the customized production-to-order application scenario. A location allocation method based on the distribution center of gravity was proposed. According to the working characteristics of the sorting and palletizing truss manipulator system, a mathematical model for the total time of equipment sorting was established, which was attributed to the problem of location allocation with the goal of minimizing the total time of horizontal movement with load. In order to solve this problem, the order-location center of gravity matrix was constructed according to the quantity and location of the goods to be picked. On this basis, according to the order of the distribution center of gravity coefficient from large to small, the orders were allocated to the corresponding cargo location one by one. The example analysis results showed that compared with the random allocation method, the algorithm could reduce the average horizontal moving time with load by about 28.14% and the average time for total sorting task by about 5.78%. The results indicate that the optimization of location allocation can reduce equipment total sorting task time of the truss manipulator and improve equipment operation efficiency of the system.