  It is widely believed that the quark-gluon plasma (QGP) might be formed in
the current heavy ion collisions. It is also widely recognized that the
relativistic hydrodynamics is one of the best tools for describing the process
of expansion and particlization of QGP. In this paper, by taking into account
the effects of thermal motion, a hydrodynamic model including phase transition
from QGP state to hadronic state is used to analyze the rapidity and transverse
momentum distributions of identified charged particles produced in heavy ion
collisions. A comparison is made between the theoretical results and
experimental data. The theoretical model gives a good description to the
corresponding measurements made in Au-Au collisions at RHIC energies.
