The invention discloses an external pressure working condition simulation test device for drilling and production equipment. The device comprises a compensation liquid cylinder and a hydraulic system,wherein the compensation liquid cylinder is independently connected with a constant pressure control system and a sealed pressure container, and the sealed pressure container is also connected with apressure boost system. The device is practical and economic, and the problem of pressure fluctuation since the structural volume of deep water petroleum drilling and production equipment changes or materials adsorb water or discharge water when the deep water petroleum drilling and production equipment caries out an external pressure experiment can be solved, pressure in the sealed pressure container can be accurately compensated or balanced, the stress situation of deep water equipment can be truly simulated, and experiment data can provide a basis for the development and the application ofthe deep water equipment.