The invention discloses a fixing structure of a frame and a separation board used for the frame, and whereby the inclined angle of the frame can be easily changed, and the assembly of the frame can be easily carried out. The fixing structure of the frame comprises a rafter seat (10)(a first frame); the separation board (50)fixedly disposed on the upper part of the rafter seat (10); a rafter (30) (a second frame), which is disposed on the separation board, and is crossed with the rafter seat (10); a clamping member (70) disposed on the upper part of the separation board (50); a carrying surface (52), which is disposed on the separation board (50), and abuts against the lower surface of the rafter. The rafter (30) can be clamped by the separation board (50) and the clamping member (70), and the rafter (30) can be fixedly disposed on the rafter seat (10).