The invention belongs to the technical field of embedded computers, and relates to a train digital broadcast controller based on HomePlug. The train digital broadcast controller comprises a main control module and a communication module. The main control module is composed of a main control chip and a peripheral circuit thereof, the main control module is responsible for the initialization of a train digital broadcast system, clock synchronization, fault monitoring and management, control and processing of audio and video streams, and operation of an MVB network high layer protocol. The communication module is composed of a USB submodule, a HomePlug power line carrier network submodule, an Ethernet submodule, an RS232 submodule and an MVB submodule. The communication module provides data access portals for log recording of network communication and the train digital broadcast system, program update and the debugging of the train digital broadcast controller. The functional modules workin coordination to form a complete train digital broadcast controller. The train digital broadcast controller provided by the invention can be applied in the fields of bullet trains, city subways, light rails or the like of the rail traffic system.