Spatial and time resolution of thermal scalar field and velocity fields are different in turbulence thermal convection. A multiple-resolution parallel direct method for DNS with two different girds is presented to solve the problem of huge computational cost in simulation of turbulence thermal convection with very high Rayleigh numbers. A constant translation interpolation method of speed was designed to meet continuous equations at each finer gird in data transformation between coarser gird and finer gird. Simulations of 2D turbulence thermal convection with very high Rayleigh numbers show that computational cost is reduced an order of magnitude by using this method. Small-scale eddy-like plumes, that move rapidly in thermal convection, are well performed in instantaneous temperature fields. It is consistent with results with a single gird. Difference of Nusselt number obtained by two methods is below 1%.