The top down method is the method by which anyone constructs from top to bottom to build an underground station.For this, first we make D-wall around it and then plunge columns are formed. When de-wall construction, the couplers are provided at each level for slabs in d-wall steel cage. after that The top sub constructs, while constructing the top slab, the opening cutouts are left for the exits, followed by the cutouts excavator machines engaged in excavation. Then in same sequence firstly concourse slab and in last base slab will be construct.