The invention discloses a simulation device for human body pleuroperitoneal cavity movement caused by breathing. The simulation device comprises a workbench, a base, a support, a drive motor, lead screw, a slide block, a push plate, a needle cylinder body, a needle cylinder piston and a push rod, wherein the base and the support are sequentially arranged on the workbench, the drive motor is arranged on the base, the lead screw is connected with the output end of the drive motor through a coupling, the slide block is arranged on the lead screw and can move leftwards and rightwards along with rotation of the lead screw, and the push plate is perpendicularly arranged at the top of the slide block; the needle cylinder body is arranged on the support, a needle cylinder piston is arranged in the needle cylinder body, and the push rod is connected with the exterior of the needle cylinder piston; the push rod is fixedly connected with the push plate, meanwhile a needle nozzle of the needle cylinder body is provided with a balloon for in-vivo simulation, and the outer side of the balloon for in-vivo simulation is sleeved with balloon for body surface simulation. The simulation device has the advantages that relevance three-dimensional movement of the chest wall body surface and in-vivo tumor generated when a human body breathes is represented, an accurate movement model is provided for breathing tracking and positioning research of tumor radiotherapy, and the accurate positioning function of breathing motion compensation on the image-guided radiation therapy.