The invention provides a breakwater construction monsoon period protection method based on cemented rock blocks and belongs to the field of protection of breakwaters. The method comprises the steps that firstly, the positions, needing to be protected, of a construction period breakwater during a monsoon period are confirmed; secondly, the rock blocks used for filling the protection positions serveas cementing objects, and the filling degree of density of the rock blocks is confirmed; thirdly, the matching ratios of cementing materials are confirmed; fourthly, regarding the underwater portion,water-solubility macromolecule polymer solving liquid is put into seawater, meanwhile, the underwater cementing material is poured, and underwater cemented plates are formed; and fifthly, regarding the overwater portion, the overwater cementing material is poured, and relying on part of gaps between the overwater cementing material and the self-supporting filling rock blocks, overwater cemented plates are formed. According to the method, the breakwater temporary protection construction work procedures are simplified, the construction efficiency is improved, and the cost is lowered.