A dynamic method is proposed to analyze the beam directing stability in both time and space domains aiming at solving the expression of the effects caused by micro-vibrations of optical components. Based on the structural modal analysis and vibration effects caused by optical components, the vibrational models of optical components are built by combining structural modality and optical system. A spatial filter in SG-II facility is numerically simulated as an example based on the method, and the temporal distribution and spatial distribution are analyzed.