Abstract:The ultrasonic flowmeter with transit-time difference method can realize the flow measurement by detecting the propagation time of ultrasonic signals between the transmit and receive from the transducer. The resonant frequency of ultrasonic transducer and the phase and amplitude changes in the process of ultrasonic signal propagation will affect the measurement precision of the arrival time of ultrasonic signal, and the measurement accuracy of ultrasonic flowmeter is affected finally. The precise measurement for arrival time of ultrasonic is one of the effective way to improve the measurement accuracy of ultrasonic flowmeter. The processing and acquisition circuit of the ultrasonic signal transmitted and received are designed and researched by the paper. The experimental results and experimental data are obtained and the experimental analysis and conclusionare given. The way to improve the measurement accuracy is given by software algorithm.