The invention relates to a supporting seat for a simply supported beam bending test and a simply supported beam bending test device. The supporting seat for the bending test of the simply supported beam is provided. A first supporting seat comprises a first supporting beam, a first bearing seat, a first bearing, a first rolling body and a first supporting plate; a second supporting seat comprisesa second supporting beam, rail groove seats, second bearings, a second rolling body and a second supporting plate; the rail groove seats are provided with rail grooves, the two second bearings are inrolling fit with the corresponding rail grooves, and gaps are formed between the first rolling body and the upper surfaces of the first supporting beam and between the second rolling body and the upper surface of the second supporting beam; the invention further relates to the simply supported beam bending test device. The device has the advantages that the rolling bodies and the corresponding supporting plates are fixed together, irregular sliding and side tilting between the rolling bodies and the supporting plates in the turnover process are avoided, and meanwhile in order to meet test requirements, the test device is ingenious in design, simple in structure and very practical.