Self-adaption Coriolis mass flow meter phase difference detection method

The invention provides a self-adaption Coriolis mass flow meter phase difference detection method used for detecting the phase difference between a first sine wave signal and a second sine wave signal. The method includes the steps that the first sine wave signal and the second sine wave signal are processed firstly and are made to have the same amplitude and frequency; the first sine wave signal and the second sine wave signal are added, so that a third sine wave signal is obtained and processed; two frequency converted sine wave signals are obtained by multiplying the third sine wave signal by the first sine wave signal and the second sine wave signal respectively; subtraction operation is carried out on the two frequency converted sine wave signals so as to obtain a mathematical function based on the phase difference between the first sine wave signal and the second sine wave signal. The measurement accuracy and correctness are improved to the maximum extent by accurately detecting the phase difference of a sensor, and the measurement accuracy can reach the national standard (ns) level.