It is known that if the dispersion of one channel of the Michelson interferometer in the optical coherence tomography(OCT) system does not match the other,the interferogram envelope will be broadened so that the axial resolution will be decreased.The influence of unbalanced dispersion between the two channels of michelson interferometer,on the axial resolution in the OCT system is analyzed and an on-line method based on the spectral interference pattern and nonlinear curve fitting is presented to measure th...