Abstract: The Weighted Amplitude Wave Superposition (WAWS) method and the Proper Orthogonal Decomposition (POD) technique are first introduced. Then the POD technique combined with a wind field reconstruction method for a flat roof is studied. And also, wind field extension using the B-spline interpolation and the wind field reconstruction method are verified. On the basis, a two-step simulation algorithm to generate wind field is presented for roof structures. Numerical examples prove that the presented algorithm is accurate and efficient. Especially the engineering example, a wind field simulation of the roof of Foshan Century Lotus Stadium, shows that the proposed method is advantageous for the wind-resisting analysis of a large roof.