Projecting method and system

The present invention provides a projection method and its system, used in the field of network interconnection technology. The described projection method includes the following steps: utilizing sender indirectly connected with projector to respectively make real-time transmission of every screen image data or image data of every screen change region; and in the receiver directly connected with projector real-time receiving every screen image data or image data of every screen change region, and making the received image data be undergone the process of restoration treatment. The described projection system is formed from first terminal, projector connected with described first terminal and several second terminals connected with network formed between first terminals. The second terminal includes sending module for real-time sending image data, and the first terminal includes receiving module for receiving image data and restoration module for restoring image data.