  We present a novel interpretation of the thermodynamics of perfect fluid dark
matter (PFDM) black hole based on Misner-Sharp energy, and then investigate its
evaporation behavior. We find that the ratio between dark sector initial
density and black hole horizon radius significantly influences black hole
evaporation behaviors. We demonstrate that the presence of the dark sector can
significantly extend the lifetime of a black hole which is similar to the
Reissner-Nordstrom case. Our work reformulates the thermodynamics of PFDM black
holes and points out the existence of long-lived black holes in the presence of
the dark sector.
