Against oilfield injecting well with high pressure water or high temperature and high pressure water steam, we developed the high temperature and high pressure detecting system, this system can achieve real-time on-line monitoring of the temperature and pressure of oil well. It is of great significande to improve oil production and increase oil recovery ratio. This tystem is capable of 24-hour monitoring and the sensor can work long years in the oil wells. Distance measurement can be realized so that the operator can learn the pressure at home. This system also can achieve multi-well multiplexing and unified supervision.