The JCT-VC is developing the next-generation video coding standard which is called a high efficiency video coding (HEVC). In the HEVC, there are three unit in block structure: coding unit (CU), prediction unit (PU), and transform unit (TU). The CU is the basic unit of region splitting like macroblock. The CU concept perform recursive splitting into four blocks with equal size, starting from the treeblock. We use mode information of the current CU to avoid unnecessary CU splitting process. To reduce more computational complexity, we propose a depth range selection mechanism (DRSM) by selecting adaptive depth range. The depth range selection mechanism provides an effective splitting by performing just CUs in want of process. The experimental results show that the proposed algorithm can achieve about 48 % of reduction in encoding time for RandomAccess HE compared to the HEVC test model (HM) 6.0 encoder with BD-bitrate loss of 1.2 %.