The invention relates to a large-depth-of-field optical method and system based on aberration balance and control. Aberration balance and control are carried out on an initial optical system without aberration correction and optimization, so that scenes at different object distances in a large depth-of-field range are processed by the optical system to obtain blurred images having certain image quality degeneration characteristics on an image plane; according to characteristics of the transfer function of the system, clear images in a corresponding depth-of-field range are restored based on adigital filtering principle, so that achieving objectives of extending the depth of field. Compared with the conventional optical system, the optical system provided by the invention has characteristics of a large depth of field and a large focal depth; and the system is obtained by carrying out aberration balance and controlling on the optical initial system. The system is operated simply; and observation is carried out on the display screen conveniently. The system is suitable for the security and protection, surveillance and observation and can be used for military and civilian application.