When fluid flows through the probe, a high-pressure distribution area is generated in its front, and the pressure in the high-pressure distribution area is slightly higher than the static pressure of the pipeline. According to the Bernoulli equation principle, the velocity of the fluid increases as it flows through the probe, creating a low-pressure distribution area at the back of the probe. The pressure in the low-pressure distribution area is slightly lower than the static pressure of the pipeline. After the fluid flows through the probe, a partial vacuum is generated at the back of the probe, and vortices appear on both sides of the probe. The cross-sectional shape, surface roughness, and position of the low-pressure tapping hole of the average velocity flow probe are key factors determining the performance of the probe. The stability and accuracy of low-voltage signals play a decisive role in the accuracy and performance of the uniform velocity probe. The flow probe can accurately detect the average differential pressure generated by the average velocity of the fluid. The flow probe has multiple pairs of pressure tapping holes arranged according to certain criteria in the high and low pressure areas, making it possible to accurately measure the average flow velocity.