The invention provides grain flow-measuring method and device. The grain flow-measuring device comprises a correlation-type photovoltaic sensor and a signal-processing circuit, wherein the correlation-type photovoltaic sensor is arranged in the middle of an elevator of a combine harvester and comprises a light emitter and a photovoltaic detector, the light emitter is used for emitting near infrared light, the photovoltaic detector is used for detecting the near infrared light penetrating through the elevator and outputting a photocurrent signal according to a detection result, and the signal-processing circuit is electrically connected with the photovoltaic detector and is used for receiving the photocurrent signal output by the photovoltaic detector and acquiring a grain flow value according to the photocurrent signal. The technical scheme of the embodiment of the invention can be adopted to solve the problems of low measuring precision and inaccurate measuring result of the grain flow-measuring method and device in the prior art and effectively improve the grain flow-measuring precision.