In digital speckle interferometry, inhomogeneous illumination on or reflection from a tested object will lead to inhomogeneous fringe pattern, and even make the fringe missing. On the basis of analyzing the principle of shearing speckle interferometry and assuming that principal value of speckle phase difference obeys the uniform distribution between -π and π,a method for correcting the substracted fringe pattern modulated by uneven light intensity is proposed. This method is to construct a new function, which can eliminate background light intensity in small areas and remove the term modulated by light intensity. Thus, the fringe pattern becomes homogeneous. It is applied to shearing speckle interferometry to test a piece of aviation composite materials suffering strong impact, and the fringes which hide in dark areas are displayed. It shows the validity of this method to reduce the influence of uneven light intensity on speckle fringe pattern.