In order to solve the problem of sig nal distortion in the process of uniform sampling complied by the overlapping multiple fiber Bragg gratings (FBGs),a new sampling method is proposed.The new way is non-uniform sampling which is implem ented by the sine wave with random variation cycles.This way of sampling is successfully appl ied to the tunable Fabry-Perot (F-P) filter FBG demodulation system.The experimental resu lts of the FBG demodulation system confirm that the phenomena of signal distortion are successfully solved b y the non-uniform sampling algorithm,the original signal can be sampled by the m easured signal whose frequency is below the Nyquist sampling frequency,and the ba ndwidth of signal sample is also improved.