The analysis method of fluctuating wind-induced background response and resonant response which take into account the modal coupling effects, the coupling component between background response and resonant response of large-span roofs are derived based on the random vibration theory. Furthermore, the theoretical combination formulas of total fluctuating wind-induced response including the modal coupling effects are proposed, on the basis of this, the coupling effect modification coefficient is introduced, and do a simplified analysis for the proposed combination formulas according to the dynamic characteristic of structures and the characteristic of fluctuating wind loads, as a result, the corresponding practical combination formulas are obtained, which can be used to combine the background response, resonant response, and the coupling component between them efficiently. At last, the effectiveness of the proposed method is verified by the combination of fluctuating wind-induced background response and resonant response of National Stadium main roof structure.