In view of the fact that the availability of well water and the electric energy comprehensive utilization rate are low in surface irrigation under low-pressure pipeline of water delivery; a new idea of applying frequency control technology to a low-pressure pipeline was proposed in this paper, which allows the pump to operate under the condition of constant discharge at varied pressures. On the basis of the field experiments, the energy-saving feasibility and effectiveness of the idea were analyzed. The experimental result shows that the capacity of pipeline water outlets consistently equals the design capacity of the water supply well; the water supply well pump can continually operate at the optimal working condition region; and the energy-saving rate of this experiment is 37.3%～82.6%.