Drilling casing and method of performing fast drilling and completion of large-borehole multilateral well

A drilling casing includes a casing wall and several sand control apparatuses disposed on the casing wall in a spacing. Each sand control apparatus includes a sand control net, a sealing steel sheet and a sealing rubber plug. A plurality of mutually-paralleled sand control meshes are disposed on the sand control net. The sand control mesh exactly faces the sealing steel sheet. The sand control net is connected with the sealing steel sheet through a steel pin. Further, a method of performing fast drilling and completion of a large-borehole multilateral well by the drilling casing includes forming a main borehole by drilling to a destination well depth at one time with a large-size drill bit, drilling a lateral borehole in a natural gas hydrate reservoir by using the drilling casing, and taking out the drill bit for completion. The method is applicable to various natural gas hydrate extraction manners.