Multi-branch well drilling and completion pipe string and construction method

The multilateral well hole well completion pipe string comprises a guiding shoe, a screen pipe, a sealing assembly, an anchoring assembly and a guiding assembly which are sequentially arranged from bottom to top. The sealing assembly comprises a first coupling, a central pipe, a valve head and a sealing pipe which are sequentially connected through threads, the first coupling is used for being connected with the anchoring assembly, and the sealing assembly is connected with the screen pipe through a second coupling; a soluble sealing structure is arranged in the sealing pipe; a rubber sleeve sealing structure is sleeved outside the central pipe; the anchoring assembly comprises a lower connector, a supporting pipe and a whipstock which are connected in sequence, the lower connector is connected with the first coupling in a sealed mode, the lower portion of the whipstock is connected with an anchor fluke which can be expanded outwards to be expanded and anchored, a hydraulic cylinder sleeve is arranged outside