Integrated thermal-structural-optical analysis is an effective technique for optical and mechanical system design and developing.The technique has been used to analyze a spaceborne telescope.Firstly,thermal analysis is carried out with Ansys software.Then Zernike polynomial is used to transfer data from one program to another.An application program is made with VC++ to implement Gram-schmidt orthogonalization.That makes up a comprehensive and intact analyzing process for optical system.Practice proves that this method is correct,reliable and effective.It is useful for the optical and mechanical design of systems such as telescope.