The measurement result is affected seriously if the connection part of the dual metal FBG sensor has sliding situation during measurement process. For reducing the influence, the utility model adopts a serial-connection structure, namely the middle part of a metal base is fixed with the middle part of a metal long strip, two gratings are respectively connected between the ends of the metal base and the metal strip to form two measurement points. In this way, when a certain connection part has sliding situation, the observed values of the two measurement points are inconsistent; when no sliding situation occurs in all the connection parts, and the temperature is changed, the observed values of the two measurement points are consistent. Thereby, the serial-connection FBG (fiber Bragg grating) high sensitiveness temperature sensor can judge if the connection part has sliding situation.