The demodulation speed has become the key issue limiting the application of fiber optic Fabry-Perot nonscanning correlation demodulator.A fast fiber-optic Fabry-Perot (F-P) nonscanning correlation demodulator based on Super Luminescent Diode(SLD) was proposed,its principle and signal characteristics were analyzed.To improve the signal stability,envelope detection based on wavelet was presented.Theoretical calculations show that the error of the result is only 0.33% with this algorithm,while the error is 4.33% without it.A experimental prototype was made and tested,when the demodulation speed is 1.5 KHz,the demodulation erorr is only 5 nm with this algorithm.The experimental results indicate that envelope detection based on wavelet can improve the demodulation stability and accuracy of the fast fiber optic Fabry-Perot nonscanning correlation demodulation system,providing a stable and efficient algorithm for the fast fiber optic Fabry-Perot nonscanning correlation demodulation system.