Huge computational complexity of multiview video plus depth (MVD) coding is an obstacle for putting MVD into applications. A fast macroblock mode selection algorithm is proposed to reduce the computational complexity of multiview depth video coding. The proposed algorithm, implementing on a joint coding scheme, combines an effective prediction mechanism and an object boundary discriminating method. The prediction mechanism which is designed based on the macroblock mode similarities reduces the number of macroblock mode candidates in depth video coding. The object boundary discriminating method extracts the regions, which are with discontinuous depth values and important for virtual view rendering, by using macroblock deviation factor. Experimental results show that the proposed algorithm can significantly promote the coding speed of depth video by 2.00-3.40 times, while maintaining high rate distortion (RD) performance in comparison with the full search algorithm.