The invention relates to a novel non-pressure irrigation rig. The water outlet valve of a water supply tank is opened, irrigation water flows into a water level control tank, when the water level of the tank is higher than h1, an intake tube is submerged, air suction is changed into water inflow until the water level in the intake tube is equal to the water level in the water supply tank, the irrigation water does not flow into the water level control tank, the water level of the tank is stabilized at the water level slightly higher than h1, the irrigation water enters into a filling area at the upper part in a U-shaped slot by virtue of a permeable cover plate and a sand inverted filter from the bottom in the U-shaped slot of the irrigator, a soil saturation water layer which is at the same height of the water level of the water level control tank and is lower than the upper edge of the U-shaped slot, water of the saturation water layer rises to the root layer of a crop in a capillary water way, a crop consumes water to cause the water level of the water level control tank to be lower than h1, the intake tube comes out of water surface, air is sucked in air bubbles, the irrigation water flows into the water level control tank, the water level rises to submerge the intake tube again, the crop consumes the water to cause the water supply process to be repeated, the output of supplying water is increased or reduced along with water consumption, irrigation is adaptive, and the irrigation rig is simple to operate and is convenient to use.