For multiview video generation from 2-D video sequences, the most important stage is to efficiently synthesize the corresponding depth maps for all video frames. The depth map generation involving precise object segmentation and depth assignment requires intensive computation and human assistance which could be costly and possibly inconsistent. To achieve reliable depth map generation, an efficient depth map interpolation method from the existing pairs of keyframes and their corresponding depth maps at the both ends of video scene is presented. The proposed method contains forward/backward motion alignment, block-based updating, object-based updating, frame selection mechanism, and depth adjustment. Experimental results show that the proposed method can generate the depth maps successfully after objective and subjective evaluations. We believe that it could greatly help to achieve multiview video generation from 2-D video sequences effectively.