The pair-wise thermal entanglement in a four-qubit Heisenberg XXZchain is investigated to study the role of anisotropy when anexternal magnetic field is included. It is found that pair-wiseentanglement is absent between nearest- and next-nearest neighbouringqubits with anisotropic parameter Δ⩽−1. For twonearest-neighbouring qubits, increasing the parameter can not onlyinduce the entanglement, but also extend the entanglement region interms of magnetic field B and temperature T. For twonext-nearest-neighbouring qubits, increasing anisotropic parameter canshift the location of the entanglement and control the extent of theentanglement in terms of magnetic field at a finite temperature.