Abstract: In the spectrometer, a cone, used to mount eight multilayer-mirrors, was combined with a central collimation device to obtain the required angles of multilayer-mirrors. Therefore the system could be collimated easily as a whole. 3-D model of the spectrometer was created and its finite-element analysis was completed by using ANSYS. Static analysis results show that the biggest distortion on the collimation device is 0.016 mm in the direction of y axis, which is the effect of gravitation and might be eliminated by increasing the thickness of the part. Besides, model analysis could identify some noises that should be avoided in operational environment. Those all are theoretical foundation for spectrometer’s precision.