Considering both the opto-mechanical design and the image quality analysis of the 1.23 m aperture telescope, we build the opto-mechanical system which can fit the diversification of elevation from 0°~90°. The opto-mechanical system can meet the requirements of imaging of the telescope. However, there are some deformations in the tube of telescope with the diversification of elevation due to the gravity, and they result in distortion of the image. The main influencing factor of the diversification of elevation to the telescope is defocusing, and some material compensation methods are proposed to satisfy the requirements of observation. Meanwhile, some feasible opinions for the observational experiments and upgrading of telescopes with 1.23 m or more larger aperture are given.