The invention discloses an effective load space cabin structure applicable to an orbiter, comprising a cabin body and cabin doors; the cabin doors are connected to the cabin body; the cabin doors can open and close the cabin body; the cabin doors are two symmetrical opposite-opening structures, and every cabin door comprises an inner skin, an outer skin, main force bearing beams, honeycomb cores, a reinforcing rib and a heat protecting structure; the honeycomb cores are located between the inner skin and the outer skin; a guide flow slot is arranged on a contact position of the honeycomb cores and the outer skin, the reinforcing rib is arranged between the honeycomb cores, and connected to the main force bearing beams; three cabin door locks are evenly distributed on the main force bearing beams, the two cabin doors are locked to each other in the process of closing; the thermal protecting structure is arranged on the outer skin, and arranged in a staggering manner; the vapor return absorption of the surface of the thermal protecting structure under the natural environment is not more than 0.15%, thus the effective load cabin door structure is high in structural rigidity, good in structure compatibility and sealing property; meanwhile, the effective load space cabin structure can meet integration and lightweight requirements at the same time.