The invention relates to a train under-vehicle fire prevention intelligent monitoring system and a train under-vehicle fire prevention intelligent monitoring method. The train under-vehicle fire prevention intelligent monitoring system comprises an under-vehicle monitoring device, a data storage unit, a data intelligent processing unit and a display unit, wherein the under-vehicle monitoring device is installed on a traction transformer accessory, and comprises an image acquisition device used for acquiring an image and a fire detector used for acquiring fire alarm information; the data storage unit is connected with the under-vehicle monitoring device; the data intelligent processing unit is connected with the data storage unit, and is used for analyzing and judging the image and the firealarm information, determining whether a fault occurs and positioning a fault point when the fault occurs; the display unit is connected with the data storage module and the data intelligent processing module; and the data intelligent processing unit is provided with an image analysis module and an abnormal fault identification module. The train under-vehicle fire prevention intelligent monitoring system and the train under-vehicle fire prevention intelligent monitoring method can monitor the external abnormal situation of a traction converter in real time, find the fault in time and positionthe fault point precisely, store and display the monitoring video in real time, facilitate the train staff to grasp the running condition of the under-vehicle traction converter in real time, carry out timely maintenance on the traction converter, and ensures safe driving.