The invention discloses a bearing load identification method based on strain signals of three cross sections of a rotating shaft. According to the invention, by testing the strain signals at the three cross sections at two ends of a bearing, the bearing load is identified. The invention has the advantages as follows: (1), compared with the traditional strain method, the method provided by the invention adopts a local modeling method, so that the problems of strain measurement error accumulation, transmission and divergence are avoided; and compared with the traditional integral modeling method, the bearing load identification method has the advantages that the structure of the shaft section nearby the bearing is simple, a mathematical model can be built up more accurately, and the modeling error is less; (2), the testing work load is small; strain testing points can be arranged nearby the bearing, and point distribution at the middle part of the rotating shaft, which requires opening the cylinder, is not required; and (3), the bearing load can be tested under a low-speed dynamic state, so that the actual load condition can be reflected more truly.