In this research, we aim to move the flat plate to the work area when assembling by using the double arm in the assembly operation by the robot, and to improve the delay of work by fixing the flat plate etc. At that time, Construct an action plan by applying constraints such as gravity to the planning of the robot to be assembled.The proposed method searches the assembly posture for each 3D object and compares the work area And the conflict of the robot itself. After that, we construct a robot pass plan by executing Rapidly exploring Random Tree (RRT) cite 1-1 considering gravity equilibrium.In this paper, first of all, data acquisition by grasp planning, assembly considering gravity equilibrium Attitude search, grasping and collision of assembly posture and searching method of inverse kinematics, RRT taking gravity equilibrium into consideration After that, we show the actual machine and verify the proposed method.As a result of operation, multiple objects with gravity balance Automatic assembly plan of things was realized.