Discontinuous deformation analysis (DDA) method benefit greatly in discontinuous deformation problems, whereas contact disposing and open-close iteration used in DDA cost significant amount of time. In order to improve the computational efficiency of the contact searching in the DDA method and maintain high accuracy, an improved contact searching algorithm is developed by changing the contact searching mode within the distance criterion. By increasing the pre-judgment, the number of corner points that need to be determined are reduced before contact searching. Two types of angular-edge contacts are distinguished and the search of these two angular-edge contacts is assigned to different loops, which changes the contact searching logic under the distance criterion. Two computational models verify the accuracy and efficiency of the improved program. Model 1 is used to test the program under various contact conditions with improved accuracy. Model 2 is employed to calculate the Donghekou landslide with improved efficiency of about 10% under the premise of guaranteeing the accuracy of the calculation results.