Abstract: With the changes of the military combat environment and tactical requirements, the countries all over the world have been demanding more and more high-level combat protection capabilities against combatant vehicles themselves. Therefore, the development of vehicle-mounted overhead remote-controlled weapon systems has become more and more important for the military of all countries. In this paper, the optimal placement of on-board weapon station elements and the human operating environment arranged in the vehicle were studied based on ergonomics. According to the human-machine function knowledge, the human spine was simplified into a computable classical theoretical mechanics model to parameterize the comfort of the human spine and obtain the optimal range of comfortable backrest angle of the human body. And considering the geometric constraint of the human body, the coordinate matrix algebraic operation was taken to get the comfortable operation and display range for shooters.