Abstract: Viewing from a new angle, the authors of this paper put forward a CAC-based general multi-focal projection with much flexibility and universality. In addition to an introduction to the basic principle, the paper offers a few projection formulas which satisfy the complex demands of users, and some corresponding examples shown by sketches as well. The authors hold that most existing variable-scale projections and multi-focal projections can be generalized or generated by employing the proposed method, and that wider applications can also be made.