The invention relates to a gas irrigation system for providing CO2 or air flow for plants and application thereof. The gas irrigation system is composed of an air source (1), a gas source (2), a gas distribution device (3), a gas concentration determinator (4), a gas concentration sensor (5), a gas flow controller (6), a gas conveying pipeline (7) and a gas distributor (8). The gas irrigation system provides CO2 gas for the plants, or breezes to the crops so that the crops can do stretching motion, or blows with strong wind, which is beneficial for deepening roots and thickening stems of the plants and reducing disease and insect damage and mould breeding. The gas irrigation system is combined with a drop irrigation and micro-sprinkling irrigation system or used in cooperation with the drop irrigation and micro-sprinkling irrigation system, which is a new method for increasing the crop yield and improving the crop quality.