To predict the buffeting internal forces of bridge components under complex incoming wind, the linear transformation relations between internal force of bridge components and their deformation were discussed in probability and statistics terms. The present paper deduced the multiple linear regressive model between the internal force and its deformation. Verification analysis is also performed to make sure that the regressive model is of great significance and can be applied in the engineering. Using the regressive model, the internal forces induced by buffeting under complicated incoming wind are predicted. This methodology can directly transform the buffeting displacement of bridge under skew wind achieved from wind tunnel test into internal force of bridge components, without using the complex theory of buffeting analysis under skew wind.