The Tianwen-1 high-resolution camera adopts an off-axis three-mirror optical system， with a high precision index， complex structure， and short development cycle. In view of the above requirements， the computer-aided alignment technology of the off-axis three-mirror optical system is thoroughly investigated and applied to the alignment process of the main optical-mechanical structure of the Tianwen-1 high-resolution camera. The application of this technology causes the alignment index of the main optical-mechanical structure of the camera to converge rapidly. The average system RMS is better than λ/14 for each field of view and the average transfer function is 0.381 at the characteristic frequency of 57.1 lp/mm. A series of environmental simulation tests， including a mechanical test， temperature cycling test， and weightlessness adaptability test， was conducted on the main optical-mechanical structure. Following the experiments， all the technical indexes changed only slightly， thus meeting the requirements of the overall design indexes. Finally， Tianwen-1 was successfully launched， and clear images of Mars were sent， thus proving the effectiveness of the computer-aided alignment technology.