Research methods: An introduction in details was given to the structure and features of power monitoring system for straddling monorail transportation in Chongqing, mainly to the system distribution, structure of communication system and software structure of communication system of master station in control Centre as well as the structure of automatic system in substation. The analysis was made of the causes for the problems of equipment in substation being out of service frequently and losing communication data packet, and the commissioning and tests were done to them repeatedly.