Abstract: The structural response of elastic aerocraft in atmosphere due to gust excitation was studied in this paper. The uncertainty parameters describing the problem of gust response are modeled as interval sets. The interval analysis method is based on interval extension and Taylor series expansion, which are combined with finite element method. The proposed method can be used to estimate the intervals of structural responses, requireing the intervals of uncertainties only, hence can be used to solve complex aeroelastic dynamic problems with uncertainties. Numerical example demonstrates the efficiency of interval analysis method by comparing its results with probabilistic method.