The utility model discloses an embedded K-type thermal couple sensor used for a temperature monitoring of a heat insulation layer. The sensor includes a metal protection tube and a K-type thermal couple. A hot end of the metal protection tube is enclosed. The K-type thermal coupler is arranged in a tube hole of the metal protection tube. Hot ends of two thermal couple wires of the K-type thermal couple are welded fixedly and cold ends of the two thermal couple wires extend out of the metal protection tube. A space between the two thermal couple wires and the metal protection tube is filled with Magnesia powder. An end of each of the two thermal coupler wires extending out of the metal protection tube is welded to a compensation lead. A cold end of the metal protection tube is provided with a connection sleeve extending backward. The connection sleeve is filled with sealing glue. The peripheral wall of the connection sleeve is provided with a lead via hole. The two compensation leads extend through the lead via holes. The two compensation leads are sleeved with insulation pipes respectively. Protection sleeves are arranged between the two insulation pipes and the sealing glue. The sensor provided by the utility model can be embedded into the heat insulation layer and measure temperatures of the heat insulation layer at different depths and is high in precision, stability and reliability.