Aiming at the problem of high rate of NRW(non-revenue water)in water supply system, the paper studied the definition and components of NRW, water balance analysis, present situation of NRW and leakage at home and abroad. Besides, the existing control techniques and methods of NRW and leakage control, such as district metering area, pipe network pressure control, leakage detection tools and pipe network modeling, have also been introduced here. In the end, reduction of NRW is a comprehensive task, so a variety of measures should be taken together to effectively improve the benefits of water supply enterprises.