Abstract: In order to verify the working performance of some aerospace products under simultaneous weightlessness and self-rotation conditions, a simulation mechanism is designed by assembling two independent mechanisms, namely, the upper single-end bearing rotary mechanism and the lower stable rotation release mechanism. This paper presents the design principle, the simulation of the rotary stress parameters, and the method and the steps for implementing the stable rotating release. The results of the high-speed spin and weightlessness test, as first carried out in China, show that with the designed device, better than the traditional test method, both the rotating environment and the weightlessness environment can be provided, and, under the premise of effectively avoiding the resonance, the test piece may fall smoothly at a speed of 3.5 r/s with a tilt angle not more than 1°, that well meets the design requirements.