English：

The short-line method is currently widely used as a construction method for segmentalprefabricated bridge. The prefabricated linear control usually adopts the six-control-point method, and thetransformation method of coordinate system is developing from two-dimensional simplification to three-dimensional space transformation. However, the current linearity control method still has some problems,such as large control point redundancy, tedious process of identifying and correcting prefabrication errors,and large differences in precision control effect. Taking the U-beam bridge of an urban subway elevatedsection as an example, a four-control-point short-line method based on the singular value decompositionspace coordinate transformation theory is proposed to control the prefabricated alignment of the section,and a lightweight algorithm is developed, which skips the independent identification and correctionprocess of the mileage, axis and elevation error of the beam section, and directly solves the theoreticalmatching coordinates of the matching section. The results of prefabricated linear control show that theactual coordinates of the left and right endpoints at the corrected segmental joints are basically coincidentwith the theoretical coordinates, which indicates that the algorithm can directly and effectively correct theprefabricated error and is a feasible new method for prefabricated linear control.