The invention provides a wide-range high-precision automatic runoff yield measurement system comprising a power supply unit, a water tank, a water outlet, a water outlet control valve, a pressure level sensor, a first liquid level sensor, a second liquid level sensor, a turbine flow sensor, a controller, and a data collector; the water tank is used for receiving runoff of a slope and storing runoff water; the water outlet and the water outlet control valve are connected to the water tank; the pressure level sensor disposed inside the water tank is used for detecting interior level of the water tank; the first liquid level sensor is disposed on the lower portion of the water tank; the second liquid level sensor is disposed on the upper portion of the water tank; the turbine flow sensor is disposed at the water outlet; the controller controls the water outlet control valve according to the first liquid level sensor and the second liquid level sensor; the data collector measures runoff and collectors and stores data according to an output value of the pressure level sensor and an output value of the turbine flow sensor. The wide-range high-precision automatic runoff yield measurement system has wide runoff measurement range and high measurement precision and is good in timeliness and high in automation level.