<p>In this paper, we consider the dynamic evolution of quantum entanglement (QE) in a two-qubit Heisenberg XXZ spin chain under the pure phase decoherence channel. First, when a constant magnetic field in the x-, y-, and z directions is applied under the decoherence channel, the entanglement, which is one of the quantum correlations, shows entanglement sudden death (ESD) and decreases with time and approaches zero. Moreover, no matter how much the intensity of a constant magnetic field is applied, and the simultaneous application of a constant magnetic field in the x, y, and z directions, QE decreases with time due to the effect of decoherence, which indicates that a constant magnetic field cannot eliminate the effect of decoherence. To solve this problem, we apply a time-varying field rather than a constant field. In other words, at each time of evolution, the quantum particle swarm optimization algorithm is used to determine the magnetic field strength so that the decoherence effect is eliminated and the QE increases. Several simulation results show that the ESD does not occur during evolution by this method, and after a certain time it reaches the Bell state, after which the QE remains at its maximum. This provides sufficient possibilities for the use of Heisenberg spin chains as quantum channels to perform quantum information processing.</p>