Abstract: Ultrasonic flow meters demonstrate high precision and instantaneous measurement capabilities in flow measurement, showing significant application potential. They are of great importance for safe oil and gas storage, low-loss transportation, and fair settlement. This paper analyzes the working mechanism of high-precision ultrasonic flow meters based on four flow calculation principles: time difference method, frequency method, cross-correlation method, and Doppler method. The influence of flow velocity and temperature on flow measurement accuracy is revealed from three perspectives: turbulence characteristics, instrument structure, and environmental factors. The interference of meter geometry changes on the flow velocity field is also discussed. This paper summarizes the error factors of ultrasonic flow meters and the technical methods to reduce errors, providing ideas and guidance for the innovation of high-precision flow meter technology through research and prospect.