  We study the entanglement entropy of fermion fields in BTZ black hole
space-time and calculate pre- factor of the leading and sub-leading terms and
logarithmic divergence term of the entropy using the discretized model. The
leading term is the standard Bekenstein-Hawking area law and sub-leading term
corresponds to first quantum corrections in black hole entropy. We also
investigate the corrections to entanglement entropy for massive fermion fields
in BTZ space-time. The mass term does not affect the area law.
