For solving the mismatching problem in computer vision,a discontinuity preserving stereo matching algorithm using variable windows in an energy minimization framework was proposed. Firstly,a dissimilarity combing intensity and gradient information was introduced.Then,according to the cost function composed of the average measurement error, error variances and the error biases of larger windows,the best window for each disparity was chosen as the matching cue,and a scanline optimization method was used to search optimum paths under the constraint of depth discontinuity. Finally,a dense disparity map was obtained by tracing optimum paths. Experimental results show that the proposed algorithm can not only process the low texture areas and depth discontinuities,but also enforce the consistency between the two neighbors. Moreover,the computation cost has almost decreased by three-fourths as compared with that of the original algorithm.