The invention provides a single fiber Bragg grating sensor for simultaneously measuring temperature and stress, which is applicable to the field of fiber sensing. The single fiber Bragg grating sensor is characterized by being manufactured by using a phase masking method as a fiber Bragg grating, and being divided into two parts with an equal length; a left half part (1) of the fiber Bragg grating is packaged in a polymer substrate (2); and a right half part (3) of the fiber Bragg grating is plated with a layer of metal protection film (4) by using a combined chemical-plating and electric-plating method. A metal plating method comprises the following steps of: cleaning dirt on the surfaces of the bare fiber Bragg grating and a tail fiber by ethyl alcohol; absorbing a layer of readily oxidizable matters on the surface of the bare fiber Bragg grating; generating a thin metal layer on the surface of the bare fiber Bragg grating; carrying out chemical-plating on the bare fiber Bragg grating; and carrying out electrical-plating the bare fiber Bragg grating. The sensor is easy to manufacture; the temperature and stress sensing sensitivity of the sensor is improved; and the sensor can be used for simultaneously measuring the temperature and the stress by only using the single fiber Bragg grating.