  Recent experimental measurements of high $p_T$ hadron spectra and jet
correlation at RHIC are analyzed within a parton model which incoporates
initial jet production and final propagation in heavy-ion collisions. The
suppresion of single hadron spectra, back-to-back correlation, their centrality
dependence and azimuthal anisotropy point to a dense matter with an initial
parton density about 30 times of that in a cold heavy nucleus.
