Abstract: In order to adjust the optical axes in the multi-sensor electro-optical system, a kind of new calibration device with a wide span of spectral-axes is introduced, of which working principle are described in detail. The Cassegrain system is the core of this device, whose primary mirror uses a new kind of adhesive and optical-centering techniques to relieve deformation, and the experimental results verify the feasibility of the proposed techniques. In addition, by precisely adjusting the Cassegrain system and multi-axes of detecting optical paths, the detection precision of this new calibration device can up to 10 theoretically. Therefore, using the proposed device and the large aperture off-axis reflective collimator, the parallelism of optical axes of multi-sensor electro-optical system can be calibrated precisely in different environments.