The present invention discloses a train set prognostics and health management system. The system comprises an on-board PHM (prognostics and health management) system, a train and ground data transmission system and a ground PHM (prognostics and health management) system, wherein the on-board PHM system analyzes and processes pre-processed data by using a constructed train set intelligent mirror model to obtain a first train set diagnosis result, the train and ground data transmission system sends the first train set diagnosis result and the data to the ground PHM system, and the ground PHM system analyzes and processes the pre-processed first train set diagnosis result and data by using a constructed ground set intelligent mirror model to obtain a second train set diagnosis result and performs comparative analysis on the first train set diagnosis result and the second train set diagnosis result so as to update the second train set diagnosis result. The train set prognostics and healthmanagement system can obtain train status perception, real-time analysis, real-time communication, intelligent decision-making and precise execution capabilities and improve the operation safety, operation and maintenance economical efficiency and intelligent design and manufacturing level of a train set.