Abstract: During the in-service inspection and the maintenance of the nuclear steam generator, a steam generator simulator is necessary for the debugging of maintenance tools and personal training. Based on the functional requirements and design requirements, a multifunctional steam generator simulator is developed. The overall structure of the simulator was designed to be 1/2 of the prototype, the composite material was used, and it is equipped with observation windows. The developed simulator is with the characteristics of compact structure, high economic efficiency and observable. Function tests verify that the simulator can be used for nuclear steam generator in-service inspection and training.