The topological constraint, entanglement, is very important factor to determine dynamics of entangled polymer. In contrast with the permanent chemical junction point in rubber network, the physical entanglement has its ‘entangled life time’ in polymeric liquids system. Therefore, identification of life time of each entanglement will contribute to understand the dynamics of entangled polymer more precisely and to develop new macroscopic rheological models of entangled polymer. Despite considerable progresses in experimental techniques, it is very difficult to find entanglements experimentally. Computationally, topological analysis such as CReTA, Z-code and so on, has been developed recently and finds entanglements successfully in polymeric liquids systems. In this study, we implemented the Z-code developed by Martin Kröger and tracked each entanglement as a function of time. Using this new algorithm, we calculate entangled life time of each entanglement from linear shot-chain to long-chain polyethylene liquids; C50H102, C78H158, C128H258, C178H358, and C400H802. Based on entangled life time, we can directly compute the segment survival probability function ψ(s,t) of each entangled polymer without any assumptions. We also calculate macroscopic rheological properties of entangled polymer from survival probability function to validate our new topological analysis algorithm. Furthermore, other relaxation mechanisms of entangled polymer such as reptation, contour length fluctuation (CLF), and constraint release (CR) are evaluated using this new algorithm. Keywords: Entanglement dynamics, Primitive path analysis, Relaxation mechanism, Tube theory