The invention relates to a molded case circuit breaker and a line loss analysis method. The molded case circuit breaker comprises a controller, and the controller is connected with a metering acquisition module, a transformer area identification module, a broadband carrier module, a current detection circuit and a release execution circuit; a node network topology structure of the current transformer area is obtained through information obtained by the transformer area identification module and the broadband carrier module, and meanwhile, electric quantity information of the metering acquisition module is acquired to form line loss analysis of the current transformer area; the molded case circuit breaker equipment adopts an integrated design, and each circuit part is reasonable in design,so that the size of the circuit breaker equipment is greatly reduced, and the installation is very convenient; the situations of messy installation lines, line flying and line breaking in the installation process are avoided, and potential safety hazards are eliminated; and grading line loss analysis and pre-judgment of the whole middle-low voltage transformer area are realized, and real-time performance, integrity, total data and the like of data acquisition are guaranteed.