Garden automatic irrigation device applied to sponge city

The utility model relates to the technical field of sponge cities, in particular to an automatic garden irrigation device applied to a sponge city, a filter layer is fixedly connected to the lower side of a permeable soil layer, a water storage bottom pool is fixedly connected to the lower side of the filter layer, and mounting columns are fixedly connected to the four corners of the upper side of the permeable soil layer; the upper ends of the four mounting columns are fixedly connected with a transversely-arranged concave frame shell, a double-rod reciprocating displacement mechanism is arranged in the concave frame shell, and sliding openings are formed in the upper sides of the two transverse ends of the concave frame shell. The water supply mechanism, the double-rod reciprocating displacement mechanism and the soil humidity sensor are arranged, the water supply pump is controlled to work by monitoring the humidity of the permeable soil layer, automatic irrigation is achieved, manpower is saved, irrigatio