Abstract: In order to clarify the accuracy and stability of the flow measurement results of the non-full pipe electromagnetic flow measurement box under the conditions of normal water delivery in the open channel and the presence of different interferences, the measurement results of different flow boxes and standard flowmeters under different working conditions were compared and analyzed. The analysis results show that the flow data measured by ultrasonic, pressure liquid level and flow measurement meet the requirements of flow measurement accuracy under different working conditions with the stan-dard flowmeter. Considering the stability of flow measurement data, the standard deviation of the data and other parameters of the ultrasonic and pressure liquid level flow measurement box are lower than those of the pressure type-A flowmeter. The error distribution range of the pressure level and flow mea-suring box is 0.047 28-0.091 34, the error distribution of the ultrasonic level and flow measuring box is between 0.047 50-0.092 50, and the error distribution of pressure level of A-type flowmeter is between 0.044 90-0.092 30. Considering the actual situation of Ningxia irrigation area, the ultrasonic and pressure liquid level flow measuring box can work under different working conditions with high accuracy, which can be promoted and applied appropriately.