Aiming at true 3D modelling of a specialshaped building unit, a photogrammetry method based on UAV (unmanned aerial vehicle) equipped with a single camera was proposed. The proposed method employs a small rotor UAV and a camera with its direction adjustable as an aerial photogrammetry system, which can automatically capture images surrounding a building unit from multiple flying heights and multiple angles of view. A real urban specialshaped building unit was modelled by two methods including popular UAV oblique photogrammetry and the proposed method. The results indicated that the proposed method achieved higher efficiency and quality of modelling without precision degraded than UAV oblique photogrammetry.