Abstract: In this paper we have derived the fundamental solutions of the flow over semi-infinite angular wings with constant load, of which the side-edge is not parallel to the free stream. The feature of the solutions is that the vortices issued from the leeward side-edge go along this edge rather than in the direction of the free stream. With the help of these solutions, we can overcome the difficulties Dillenius and Nielson have experienced in using symmetrical subdivisions to construct the finite elements for sideslipping wings, and extend Woodward method, so that it is applicable to wings with small angles of sideslip for subsonic and supersonic speeds. The problem is divided into symmetrical and asymmetrical parts, thus allowing a great saving of computer storage and operation time. Besides, a quasi-similar rule is derived from the governing equation or directly from the numerical method. The results obtained are in good agreement with those obtained by the exact theory and other methods.