The invention discloses a fixing structure of a solar cell module. A fixing hole is arranged at a groove sidewall below an outer frame sidewall groove of a solar cell assembly, the fixing hole is a long round hole, the length direction extends along the length direction of the solar cell assembly, the fixing hole has a long diameter of X, a short diameter of Y and a hole depth of Z, an assembly fixing member is a cuboid with width of X1 and thickness of Y1, an upper portion of the assembly fixing member is symmetrically provided with inwardly recessed engaging grooves in the width direction, adistance between bottoms of the two engaging grooves is X2, the width of the engaging grooves is Z2, X>X1, Y>Y1, X1>Y>X2, Z2>Z, and a lower portion of the assembly fixing member is fixed with a purlin. The structure is advantaged in that the number of spare parts is significantly reduced, the solar cell assembly can be fixed sideways or below, safety is achieved, moreover, the adjacent two solarcell assemblies can be closely arranged and installed, and a gap water leakage problem that cannot be solved through traditional solutions is solved.