Abstract: With increasing demands for the reconstruction of the existing metro line signal system, it is of great significance to upgrade the metro signal system with less impact on the existing line operation. Based on the operation and investment status of Dalian metro Line 3, as well as the development of urban rail transit signal equipment technology in China, in this paper the technical reform scheme of the fixed signal occlusion system is discussed and studied, a new design scheme for the reconstruction of existing signal system is propose.