A Single Point Of Failure (SPOF) in system operations is a weak point of system reliability. Mean Time To Failure (MTTF) of system operations is equal to the shortage component's MTTF in system. A Tier IV data center is designed to eliminate the SPOF. Data center system reliability is not only depended on the MTTF of each component in the system, but also relies on the Mean Time To Repair (MTTR) of each component. Researcher performed Tier IV DC Power Distribution Systems (PDS) through simulating software, BlockSim7. The research question is tried to investigate how to improve system reliability. Component's Inherent Characteristic (CIC) and System Connectivity Topology (SCT) are applied to improve the system reliability of Tier IV data center.