This invention provides a rendering and optimizing method and a projection method based on a CAVE system. The rendering and optimizing method includes: acquiring first visual coordinate information of a user relative to each visual plane; generating a projection channel of the user relative to each visual plane based on the first visual coordinate information; selecting a projected object in the projection channel according to a history or visual preference information instantly input by the user; and rendering a pipeline based on the projected object in the projection channel and reading a projection result. This invention can provide personalized rendering options for users in the CAVE system.