Three years experiments were carried out to investigate the effects of different soil matric potential(from-10 to-50 kPa) on the lettuce growth and water use efficiency under drip irrigation condition in North China.The results showed that with the soil matric potential decresesed at 0.2 m depth immediately under drip emitters the irrigation amount and the accumulative consumed water in whole growing were obviously reduced,but the irrigation water use efficiency obviously increased and didn't affect the tot...