The invention provides a supporting frame for a working table. The supporting frame comprises a main frame body, a first fastener and a second fastener, wherein the first fastener and the second fastener are movably arranged at two ends of the main frame body, are respectively provided with opening positions and locking positions, and rotate along the same direction, so that the respective opening positions move to the respective locking positions; when the first fastener and the second fastener are respectively positioned at the locking positions thereof, the position of the main frame body is fixed relative to the working table. Compared with the prior art, the supporting frame provided by the invention has the advantages that the operation surface of the working table is clamped by the cooperation of the first fastener and the second fastener, the fastening steps are simple, and the supporting frame is high in firmness; moreover, the smoothness of the operation surface is guaranteed. After the supporting frame is disassembled, the operation surface also has other functions, and the utilization rate of the operation surface is improved.