A rigid-soft coupled model is proposed to implement the simulation of rigid-soft hybrid robot which can't be done by the existing robotic simulation platforms. The coupled model provides an intermediate layer to couple the lower physical models of existing rigid robot simulation platforms and soft robot simulation platforms such that the two types of platforms can work together within the same framework to complete the simulation of rigid-soft hybrid robot. A system worked in the Robot Operation System for the rigid-soft hybrid robot simulation based on the coupled model is developed using Gazebo and SOFA simulation platforms. Simulation and prototype experiments on the bending process of a single soft pneumatic gripper are conducted and compared, and multi-object grasping by the rigid-soft hybrid robot is simulated. Those experiments verify that the proposed coupled model is effective to implement the simulation of rigid-soft hybrid robot.