Abstract: By using the meso-scale objective analysis data, the forcing field of the nonturbulent deformation in Richardson number tendency equation of θ coordinates is diagnosed in order to study the response relation between clear-air turbulence (CAT) and synoptic-scale and meso-scale dynamic forcing processes. The calculating results show that CAT is often encountered in the upper troposphere or near upper air jet flows. In the stable shallow layer of upper atmosphere, when micro air mass with small Ri number encounters the strong forcing field of nonturbulent deformation, because of the coupling function of dynamic forcing with Ri number, CAT would occur frequently.