Abstract: The permit range of pressure regulation in the field is an important parameter on designing constantpressure sprinkler irrigation system, and affects on the irrigation quality. By testing analysis of the conditions under a few pressure changing in the constantpressure sprinkler irrigation system，the rule of the pressure change and some common basic data, such as cycle of the sprinkler turning around, sprinkler intensity and the combined uniformity changing with the pressure were found out. The effects of the pressure changing on the average sprinkler intensity and the combined uniformity were analyzed. The cycle of pressure change has few effects on the average sprinkler irrigation intensity and the combined uniformity. But within the range of pressure changing in different time, the pressure will affect the system working significantly. According to these,the relationship of changes between the sprinkler intensity in the field and combined uniformity and the pressure were built.