The invention discloses an operating parameter detection method of stirring tank, which comprises (1), arranging an acoustic emission signal receiver on the wall of a stirring tank, (2), receiving the acoustic emission signal from the stirring tank, (3), using second-order Daubechies wavelet decomposition technique to analyze the received acoustic emission signal, using Hurst analysis to select the acoustic emission signal which Hurst value is lower than 0.5, (4), when the energy consumption ratio Ri is quickly reduced and gradually stabilized, setting the relative stirring speed as critical stirring speed. The inventive vibration receiver is non-inserting type, with simple and easy mounting, without affecting the motion or internal reaction of multi-phase fluid and without demanding emission resource. The vibration signal is generated in fluid motion, which is safe and environment friend with low demand on measurement conditions and the application in bad weather, therefore, the invention can normally work under high-temperature high-pressure condition, with sensitive reaction, low measurement error and wide application.