In order to solve the problem that dispersion in dispersive material restricts improvement of depth resolution of optical coherence tomography(OCT)with broadband optical source.a numerical posteriori dispersion compensation technique for optical coherence tomography depth-scan signals is presented.The relationship between resolution of optical coherence tomography and FWHM of optical source is analyzed.In experience,1 550 nm optical source and fiber Michelson interferometer are used to get imaging signal from planes in the water.Data of the image are compensated up to the third order optical dispersion of water and rapid optical delay line.A tunable phase factor is introduced to improve the results of compensation.Examples of dispersion compensated depth-scan signals obtained from microscope cover glasses under water and muscle tissue of mouse are presented.