Double-running staircase convenient to mount and demount

The utility model discloses a double-step staircase convenient to mount and demount. The double-step staircase comprises a base, standard sections and protective sections, bases are mounted at the bottoms of the standard knots, protective knots are mounted at the tops of the standard knots, and the multiple sets of standard knots are connected through bolts; pedals are arranged on an outer frame of the standard knot in a double-step mode, a rest platform plate is arranged in the middle of the outer frame, and turning plates are arranged at the bottom and the top of the outer frame. A handrail is arranged on the side, away from the outer frame, of the pedal. The turning plate is connected with the outer frame through a hinge, and the two sides of the turning plate are connected with the outer frame through iron chains. The pedal, the rest platform plate and the turning plate are all formed by welding third square steel and riffled plates, and the third square steel is of a rectangular structure and is welded t