Flat plate solar collector with defroster

The utility model relates to a flat plate solar collector with a defroster. The flat plate solar collector with the defroster comprises a transparent cover plate, a header, a discharge pipe, an absorber plate and a shell, wherein the header and the discharge pipe are communicated with each other and then welded with the absorber plate into a whole to be arranged in the shell, and the transparent cover plate is arranged at the top of the shell. The main technical characteristic is that the flat plate solar collector with the defroster also comprises a defrosting unit, wherein the defrosting unit comprises a defrosting pressure-relief pipe, a piston, a spring and an end cover; and the piston is installed on the inner side of a water inlet at the front end of the defrosting pressure-relief pipe and moveably sealed with the defrosting pressure-relief pipe, the end cover is provided with a through hole and connected to the tail end of the defrosting pressure-relief pipe, the spring is installed in the defrosting p