Doubly ruled surface has been widely used in architectural design and industrial design because of its beautiful shape and simple force transfer. In the paper, the condition of doubly ruled surface with arbitrary space quadrilateral as the boundary is derived, and a method of modeling doubly ruled surface based on shape factor -1≤k≤+1 is presented independent of coordinate system. The shape of a doubly ruled surface with an arbitrary space quadrilateral as the boundary is uniquely determined by shape factor k. The doubly ruled surface with space quadrangle boundary are two planes with a diagonal line when k=-1 and k=+1. The surface shape makes a smooth transition when k changes from -1 to +1, and the appropriate k value can be selected for modeling according to the bidirectional curvature requirements. Doubly ruled surface guarantees the smoothness of the surface, and the single factor k greatly reduces the storage space of the model, which also provides a reference for the quadrilateral grid modeling of complex building shapes.