Relation between black hole entropy and quantum field spin

Starting from the master equations of governing arbitrary spin fields, we calculate the free energy of spherically symmetric space-time due to arbitrary spin fields. Then we study the entropy of seven kinds of static space-times. The result shows that there is a linear relation between nonextreme black hole entropy and quantum field spin. Taking into account the degeneracy due to spin, we have a direct proportion relation between nonextreme black hole entropy and quantum field degeneracy. As for the extreme black hole, we find that its entropy is zero.