The invention relates to a hydraulic automatic root flushing machine. The hydraulic automatic root flushing machine is characterized by comprising a machine frame, wherein the middle part of the machine frame is welded with a water chute; the upper part of the machine frame is provided with a plurality of flushing buckets in parallel; each flushing bucket comprises an outer bucket and an inner bucket which is embedded in the outer bucket; the inner bucket passes through the bottom of the outer bucket; the bottom end of each inner bucket is connected with a mesh screen; the lower part of each outer bucket is provided with two nozzles; the two nozzles are connected with both ends of a tee joint through hoses respectively; the third end of the tee joint is connected with a switch valve; the switch valve is connected with a water pipe fixed to the machine frame; and the water inlet of the water pipe is connected with an external water source. The hydraulic automatic root flushing machine can replace manual root flushing, greatly reduces labor intensity, improves screening efficiency, does not damage roots with complete root systems, and ensures the reliability and timeliness of root system tests.