The experiment of non-pressure subsurface drip irrigation was conducted. The non-pressure subsurface drip irrigation, a kind of local water control irrigation. The law of outlet flow rate at different aperture diameters and the soil water status under the condition of non-pressure irrigation were studied. The results indicated that the outlet flow rate of non-pressure aperture was related to aperture diameter, soil temperature and soil water content, etc; The moving velocity of wetting front was influenced mostly by aperture diameter and initial soil water content; The larger aperture diameter and initial soil water content were, the faster moving velocity of wetting front was; The outlet flow rate was uniform under the condition of aperture diameter from 5 to 35 cm along the pipeline, and the soil water content was also not significantly changing with depth. It was proved that the outlet flow rate of 3×Φ4 mm aperture diameter at non-pressure subsurface drip irrigation could fulfill the water requirement of vegetable crop when root-age depth was 20 cm soil layer.