In order to solve the problem of single measurement parameters of fluid tester, a method of measuring fluid multiparameter by ultrasonic technique is proposed. When the propagation distance is constant, the volume flow, density, and mass flow of the fluid are obtained indirectly by using the propagation velocity of ultrasonic waves in the fluid. Because the parameters such as fluid flow and density are affected by the temperature, the temperature signal is used as the reference signal in the design to compensate the parameters in real time. At the same time, using FPGA as the control core to achieve highvelocity signal acquisition and processing, and using software interpolation algorithm to accurately realize the precise calculation of ultrasonic propagation time, the measurement results can be more stable and reliable.