The invention relates to a method for testing flow conductivity of self-supported cracks in riverfrac treatment. The method comprises the steps of: manufacturing a core test piece which satisfy closed state of the crack wall surface after pressure relief return of riverfrac treatment, drilling a phi 50*100 mm cylindrical test piece, enabling the cylindrical test piece to be orthogonal with a pre-formed scratch, splitting the pre-formed scratch to manufacture a tensile fracture type crack wall surface, dislocating the crack wall surface, smoothly grinding the end surface of the core test pieceto obtain a non-proppant non-engaged crack wall surface combination; then testing the flow conductivity of the crack, putting the manufactured core test piece into a core clamping system, simulating formation stress and temperature, setting and sending a control instruction, enabling each system to work and feed back signals, and finally, collecting the test results and calculating the flow conductivity of self-supported crack in the riverfrac treatment. The method in the invention can really reflect the tensile fracture and shear slip process of the riverfrac treatment, and reduce the process to a pressure and temperature environment under the ground to test the flow conductivity; and the test method is achievable.