Abstract: The thermal shroud is an important part of the space simulator. It provides the cold and dark conditions just like in the space environment. The traditional “components to assembly” modeling method is complex and is not very convenient to implemented, because of the special structure of the thermal shroud. The paper proposes a new fast modeling method of the thermal shroud with SolidWorks’s welding function. The modeling process of a thermal shroud for the space simulator is illustrated step by step. This method is shown to be efficient.