The greybody factors for spin 1/2 particles in the BTZ black holes are
discussed from 2D CFT in bulk-boundary correspondence. It is found that the
initial state of spin 1/2 particle in the BTZ black holes can be described by
the Poincar\'{e} vacuum state in boundary 2D CFT, and the nonlinear coordinate
transformation causes the thermalization of the Poincar\'{e} vacuum state. For
special case, our results for the greybody factors agree with the semiclassical
calculation.Comment: 14 pages, Latex, discussions adde