The utility model provides an on -vehicle rail surface hurt magnetic flux leakage detection's equipment and system, this equipment include excitation power supply, first probe, second probe, gate circuit and data collection card, and excitation power supply is to first probe, the power supply of second probe, acting as and conducting time measuring, rail that first magnetizer magnetization was detected, first array sensor pick up the magnetic leakage signal, the rail of second magnetizer after to the magnetization magnetic treatment that disappears, instantly, conduct time measuring, rail that second magnetizer magnetization was detected, second array sensor pick up the magnetic leakage signal, the rail of first magnetizer after to the magnetization magnetic treatment that disappears, gate circuit compares magnetic leakage signal and preset's threshold value, output triggering signal, data collection card, with gate circuit be connected, when receiving triggering signal, gather the magnetic leakage signal. The utility model discloses accomplish the detection to the magnetic leakage signal of rail surface hurt, and increased the detection precision, satisfied the modern railway demand of high speed development.