Abstract: To deal with the issues of scattered storage of operation log data in each unit, multiple data dump and download interfaces, and tedious and time-consuming data analysis work of the on-board equipment of CTCS3-300H train control system, the online status monitoring and intelligent analysis system for CTCS3-300H onboard equipment is designed based on the structural characteristics of the equipment. The system unifies the collection and transmission interfaces of log data for each unit of the train control on-board equipment. By use of existing train-ground wireless transmission channel, a flexible and practical train-ground data transmission scheme is designed to achieve real-time transmission of event notification message for online monitoring of train control on-board equipment status as well as two wireless download methods for fault logs: automatic download and manual on-demand download. While meeting the needs of online monitoring and fault analysis of train control on-board equipment status, the transmission volume of train ground data is minimized. By effectively utilizing the log data of train control on-board equipment for intelligent analysis, it is possible to quickly and accurately locate the cause of faults, achieve automatic fault alarms and provide fault disposal suggestions, improve the efficiency of fault emergency response and maintenance of train control on-board equipment, and provide strong technical support for the safe operation of high-speed trains.