Abstract: Large span spatial lattice structures are characterized by the existence of many natural frequencies in a narrow frequency range. Consequently, with the modal analysis method, it is difficult to contain all significant contribution modes. It has been shown that some high order modes, which contribute to wind response significantly, are likely to be overlooked because of their higher modal order. From a view point of contributions of modes to the strain energy of the system, it is suggested to make an efficient selection of dominant modes in this paper. A simple and effective method to compensate the errors owing to leaving out some high order modes is proposed. The effectiveness of the proposed method is verified through a numerical simulation of the wind response of a spherical dome.