During the actual use of ultrasonic water meters，the geometric parameters of the measuring tube may undergo creep due to factors such as stress release during processing，uneven installation stress，and environmental temperature changes，resulting in deviations from the factory calibration parameters and affecting measurement accuracy. A self-calibration method based on parameter self-diagnosis and dynamic compensation is proposed to address this issue. By monitoring the changes in key geometric parameters of the measuring tube in real-time and establishing a correction model using factory calibration data，dynamic compensation for measurement errors can be achieved. Experimental results show that the self-calibration method based on parameter self-diagnosis and dynamic compensation can effectively suppress the influence of parameter drift on measurement accuracy，enabling the ultrasonic water meter to maintain measurement accuracy similar to factory calibration over a long period of operation，and providing a feasible technical solution for the stability control of ultrasonic water meter performance.