In this paper，the supersonic damping-in-pitch derivatives of blunt body are calculated with two methods. One is simulant unsteady viscous flow field by solving N-S equations，and another is the analytic method of unsteady embeddy Newtonian theory. According to the numerical method，the precision of unsteady flow calculation is improved by using sub-iteration. Similar results are abtained through the two methods. The numerical method can be applied to general flow calculation (3＜M<20,0°＜a＜20°).