In view of the optical fiber Bragg grating(FBG) quasi distributed sensing demodulation system, a specialized study is studied. In view of mixed information, large dynamic range and other characteristics in quasi distributed sensing demodulation system, a FBG sensing demodulation system is set. Using laboratory existing composite sensor as a platform, based on the LabVIEW software, a suitable system for distributed optical fiber grating sensor demodulation is designed, which makes the temperature, pressure, flow information based on wavelength changes are distinguished intelligently and the physical quantities measured are displayed real-time through the corresponding calculation. Through this experiment, the temperature sensor, pressure sensor and flow sensor are calibrated respectively, the parameters are calculated; through the comprehensive experiment, the system identified the wavelength value of different physical quantities and displayed physical quantities directly, realized the purpose of the high precision visualization and real-time display,verified the feasibility and reliability of the system design.