  We investigate the effect of early chemical freeze-out on radial and elliptic
flow by using a fully three dimensional hydrodynamic model. We find that the
time evolution of temperature and the thermal freeze-out temperature dependence
of average radial flow are different from the results by using a conventional
hydrodynamic model in which chemical equilibrium is always assumed. We also
analyse the p_t spectrum and v_2(p_t) at the RHIC energy and consistently
reproduce experimental data by choosing the thermal freeze-out temperature T_th
= 140 MeV.
