  The thermal entanglement in Heisenberg $XYZ$ chain is investigated in the
presence of external magnetic field $B$. In the two-qubit system, the critical
magnetic field $B_c$ is increased because of introducing the interaction of the
z-component of two neighboring spins $J_z$. This interaction not only improves
the critical temperature $T_c,$ but also enhances the entanglement for
particular fixed $B$. We also analyze the pairwise entanglement between nearest
neighbors in three qubits. The pairwise entanglement, for a fixed $T$, can be
strong by controlling $B$ and $J_z$. PACS: 03.65. Ud, 03.67. -a, 75.10. Jm
