This paper gives a new dynamical convergence criterion (RSMSD) in the real space multi-slice (RSMS) method, which imposes a practical restriction in choosing dynamically the expan-sion order for the propagator between each pair of slices by using a structure-dependent trun-cation condition, so as to avoid the intrinsic computational divergence problem of the original RSMS method. The validity of the RSMSD method for dynamical diffraction calculation in HREM has been rigorously examined. It has been found that, when the dynamical criterion is satisfied, the RSMSD method gives results in good agreement with those obtained by using fast Fourier transform multi-slice (FFTMS) method but avoiding the computing divergence which can arise in the RSMS method.