We present a self-consistent quasiparticle model to investigate the thermal properties of quark-gluon plasma above the critical temperature. All effects of the interactions among the partons are contained in the thermal mass of partons, so the system may be treated as an ideal gas of the massive quarks and gluons. From the statistical mechanics, we can calculate the thermodynamical quantities without any inconsistency, and then obtain a good fit to the lattice QCD data. The results show that the main degree of freedom is from quark-antiquark pairs, even at the high temperature. Finally, the qu...
