The invention discloses a short-line-method box girder section prefabricated longitudinal full-length prestressed duct positioning device, and meanwhile discloses a method for positioning constructionby utilizing the positioning device. The short-line-method box girder section prefabricated longitudinal full-length prestressed duct positioning device is characterized in that the positioning device comprises steel pipes (1); the end diameters of the steel pipes (1) are gradually decreased; the outer diameters of the steel pipes (1) are R, and the end diameters of the steel pipes (1) are 0.3 R;PE pipes (2) are arranged outside the steel pipes (1), and the steel pipes (1) and the PE pipes (2) together form liner pipes; the PE pipes (2) are movably connected into corrugated pipes (3) in a penetrating mode, wherein the corrugated pipes (3) are buried in concrete; and anchor plates (4) and spiral steel bars (5) are arranged at the ends of the corrugated pipes (3).