In view of the problems that the existing fiber grating pH sensor can not be used for the detection of pH in the anchor cable due to its narrow response range, low sensitivity and limited application, this paper puts forward a method that fiber Bragg grating(FBG) pH sensor is embedded in the anchor cable to monitor the pH inside the cable. The working principle of FBG pH sensor is analyzed, and the FBG pH sensor is embedded in the steel strand for corresponding experimental research. The test results show that when the pH is 4-11, there is an optimum coating thickness in the FBG pH sensor embedded in the anchor cable, which makes the sensitivity of the sensor to the maximum value of pH response, and the FBG pH sensor embedded in the steel strand does not change the temperature characteristics of FBG.