  Jet quenching effect has been investigated in the direct photon production,
based on a realistic data-constrained (3+1) dimensional hydrodynamic
description of the expanding hot and dense matter, a reasonable treatment of
the propagation of partons and their energy loss in the fluid, and a systematic
study of the main sources of direct photons. Our resultant $\pt$ spectra agree
with recent PHENIX data in a broad $\pt$ range. Parton energy loss in the
plasma eventually effect significantly direct photon production from
fragmentation and jet photon conversion, similar to hadron suppression in
central heavy ion collisions. But this only causes about 40% decrease in the
total production of direct photons, due to the mixture with other direct photon
sources.
