Abstract: To determine the spatial-temporal variation of flow rate and fertilizer density for the drip fertigation machine under different pressures and the influence of hydraulic characteristics to the irrigation uniformity, the fluorescent tracer solution was applied to simulate fertilizer. In this experiment, a drip fertigation machine with proportional pump was used as research object. The results showed that the uniformity of irrigation and fertilization of the drip fertigation machine was fine under different pressures with uniformly continuous sampling method, but there were fertilizer delay time and stop lag time in application process. The two kinds of time decided the shortest application time and the best way of drip irrigation of the drip fertigation machine. Meanwhile, due to the two kinds of time, the results of fertilizer uniformity test were different when it choosed the different testing time.