Dry farmland supplementary irrigation device capable of collecting rainwater

The invention discloses a dry farmland supplementary irrigation device capable of collecting rainwater, relates to the technical field of agricultural irrigation, and solves the technical problems that the volume of accumulated rainwater of an existing water storage facility is fixed, the accumulated rainwater evaporates too quickly, and the collected rainwater is inconvenient to clean. The dry farmland supplementary irrigation device comprises a water storage tank, and the top end of the inner wall of the water storage tank is slidably connected with an extension wall; a water pump is fixedly connected to one side of the front surface of the water storage tank, an adjusting mechanism is arranged on the outer side of the water storage tank, a fence mechanism is arranged at the top end of the inner side of the extension wall, and a cleaning mechanism is arranged at the bottom end of the fence mechanism. Through cooperative work of the structures, the volume of stored rainwater can be adjusted according to the