Abstract: Dryden model is Usually used in studying the response of flight vehicle to atmospheric turbulence. For a modern flight simulator, it is necessary to generate random winds（in Dryden model or sometimes others） with a digital computer. In this paper, a theoretically stricted new method to meet this purpose is proposed. By this method, we can acquire a three-dimensional atmospheric turbulence which contains three components of wind velocity and three components of wind velocity gradient. The reliability of this method is checked by comparing with the autocorrelation value obtained from the theoretical autocorrelation value. A numerical example has shown a satifactpry result. Finally, some proposals about how to use this mathematical model in flight simulator are given.