The theoretical analysis and key technologies for high-speed railway（HSR） TPSS are needed to be studied. Firstly，a series of key basic theories and technologies of high-speed railway TPSS are described in this paper. Meanwhile，on the present development situation of traction power supply system，the new technologies are prospect such as the new power supply technology，active operation and maintenance，energy saving and improve the efficiency of energy utilization and the detection and monitoring technology. This will provide guidance for the development and application of China high-speed rail traction power supply technology.