According to the particularity of weapon equipments system,F-P demodulation method was advance and analyzed to use in Fiber Bragg Grating sensor system.how to design and choice a F-P filter was provided,and the difficulty of F-P demodulation method used in dynamic parameter detection was pointed out.scale changeable sampling technique was introduced to deal with the problem and the difficulty of circuitry design was reduced.The result of experiment indicated that the data quantum of sampling was reduced heavily at a time of F-P scan,and the efficiency of data sampling was advanced,so the speed of demodulation was advanced more than five times and it′s precision wasn′t reduced.The paper provides conditions of application and research of Fiber Bragg Grating sensing technology used in army.