Abstract：In this paper, a method of Dynamic Mode Decomposition (DMD) is proposed to analyze the atmospheric motion data, aiming at improving the understanding of atmospheric motion characteristics. The modal analysis of the 200 hPa jet is carried out by DMD method, and the main modes and their corresponding frequency and the decay/growth rate of flow are obtained. Secondly, a dynamic reduced-order model of the evolution of the 200 hPa jet is established, which can reconstruct and predict the dynamic development process of the jet. Results confirm that, the DMD method can successfully captures the flow structures of different scales of the 200 hPa jet stream flow, and depicts the differences between the flow with different frequencies by comparing and analyzing the flow field information contained in the first 6-order main modes, indicating the advantages of the DMD method in modal decomposition of complex atmospheric dynamic systems. The comparisons between the real flow fields and the reconstructed ones by the mode superposition at different times indicates that the first 6-order modes contain most information of the original flow fields and can accurately reconstruct them.