The invention discloses a fully-enclosed assembled string 
structural system, which comprises a bearing structure and a 
building envelope, wherein lattice dual-rod truss steel beams are connected with lattice dual-rod truss 
steel columns through flanges and bolts to construct portal lattice dual-rod truss steel beam columns; a plurality of steel beam columns are arranged symmetrically in parallel at certain intervals along the long axle direction of the 
structural system to construct a load-bearing light steel framework; an upper string cord and a lower string cord are connected between the steel 
beam column at the outermost end and an adjacent steel 
beam column; a 
flexible cable is tensioned by using internal steel beams; a plurality of stay poles are uniformly distributed between the 
flexible cable and lower chords of the steel beams; and the building structure is a 
film material covering a roof surface and a wall surface. The 
structural system designed by the invention has the advantages of easiness, practicability, light 
dead weight, convenience in transporting and assembling, and capability of meeting the requirement of repeated use. The invention provides a detailed construction method specific to the structural 
system. The method is easy to implement, the construction efficiency can be ensured, and the space utilization and repeated utilization ratio can be ensured. The fully-enclosed assembled string structural 
system can be widely applied to 
open type large-space light steel structural systems.