Abstract
Some new Hamiltonians are constructed via the unitary Yang-Baxter matrices. R-i,R-i+1(theta, phi) acting on a Hamiltonian H-0 which describes nearest spin-spin interaction. By the concept of concurrence, we explore the thermal entanglement of these systems. We find that the interaction of z-component of two neighboring spins g has great influences on the thermal entanglement. It not only influences the critical temperature T-c, but can also influence the critical magnetic field B-c.