[en] Vertically focused monochromator technique is an effective tool of increasing neutron intensity at sample position. Monte Carlo simulation is applied in choice of vertically focused monochromator of the high resolution neutron powder diffractometer (HRPD) at China Advanced Research Reactor (CARR). The height, curvature radii and tilting angles of the monochromator are obtained. The intensity gains of the vertically focused monochromator comparing to flat monochromator and the effective neutron beam size at sample position are given by simulation