Weak fiber Bragg grating array has been theoretically analyzed by the transfer matrix method and coupled-mode theory. Fig.1 gives the analysis diagram of weak fiber Bragg grating array Through the mathematical operation, the simulation model of the Weak Fiber Bragg Grating Array is obtained. Numerical predictions of the effects of distributed weak Bragg gratings on the reflection spectra of such a grating are calculated. This fiber with several random distributed weak Bragg gratings has been fabricated. In this paper, the number of peaks in the reflection spectrum increases significantly as the number of gratings increases, and the intensity of reflection increases.These predictions are compared with experimentally measured spectra of the random distributed weak Bragg gratings, the reflection spectra of the weak grating array are measured with an AQ6370 optical spectrum analyzer with a 0.02 nm resolution, A good agreement between the theoretical predictions and the experimental results was obtained. From comparing the experimental results to the simulation results, we figured that transmission peaks have good agreements; the central wavelength of reflection spectra of the weak Bragg grating array about simulation result is 1551.05 nm. We found that when the position and size are changed simultaneously, the reflection spectra of the weak grating Bragg array can be predicted. the number of gratings has a significant effect on the number of reflection peaks, and the larger the number of gratings, the greater the number of reflection peaks. We think it maybe because the light propagates back and forth in the grating and so on.