The invention discloses a high-temperature and high-pressure water vapor environment structural material testing device. The testing device is provided with a pipe, wherein high-temperature water flows inside and outside the pipe. The testing device comprises an autoclave, a test tube loading system, a loop system inside a test tube, a loop system outside the test tube, a controlling and measuring system and a data acquisition and processing system. The testing device which can be used for simulating the temperature, pressure, flow velocity, water chemical conditions, load and the like of a high-temperature and high-pressure water vapor environment structural material is applicable to tests in the aspects of corrosion, stress corrosion, corrosion fatigue, flow accelerated corrosion and the like of tubular specimens through complex flow and complex load coupling effect. Especially, the working conditions of different flow, different inner-side and outer-side temperatures, different pressures and different water chemistry in a heat exchange tube of a steam generator in a nuclear reaction pressurized-water reactor can be simulated to carry out related testing and research on the heat exchange tube.