In order to accurately extract the peak positions of correlation interference signals and provide a theoretical reference for the demodulation mechanism of the correlation interference of an optical wedge type fiber Febry-Perot sensor, the correlation interference signals of three typical spectral distributions of light source are numerically simulated and the obtained correlation interference signals are analyzed in detail. Moreover, the influence of spectral bandwidth on the width, amplitude and contrast ratio of the correlation interference signals is discussed under the condition of different spectral distributions. The analysis results show that the correlation interference signals have relatively small noises, sparse stripes and high signal contrasts when the light source has a Gaussian spectral distribution and a relatively large bandwidth. It is beneficial to search peaks accurately and realize a high precision demodulation.