The invention discloses a bimetallic strip drain valve. The bimetallic strip drain valve comprises a valve body, a valve cover and a valve element, wherein a mounting groove is formed in the upper endof the valve body; a valve seat is formed at the bottom of the mounting groove in the valve body; an inlet is formed in the left end of the valve body; an outlet is formed in the right end of the valve body; a valve hole for communicating the mounting groove with the outlet is formed in the middle position of the valve seat in the valve body; a communicating hole for communicating the inlet withthe mounting groove is formed in the valve body; the valve cover is fixedly mounted at an opening in the upper end of the mounting groove; the valve element is positioned in the mounting groove and used for controlling the on-off of the valve hole; an adjusting rod of which the upper end extends into the valve cover is arranged in the valve cover; a plurality of bimetallic strips are arranged between the upper end of the valve element and the lower end of the adjusting rod; a protecting assembly matched with the valve element is arranged in the mounting groove; and the protecting assembly is used for protecting the sealing surface of the valve element and scraping impurities on the sealing surface of the valve seat. The bimetallic strip drain valve is simple in structure and can protect the sealing surface of the valve element.