The invention relates to a cabin wall form, and discloses a fold-line cabin wall suitable for a floating production oil storage device. The fold-line cabin wall comprises a fold-line side longitudinal cabin walls which are arranged between two transverse cabin walls in the middle of a ship and have symmetrical left and right boards; the fold-line side longitudinal cabin wall on each side comprises a middle straight cabin wall as well as front and back oblique cabin walls; the length between the two transverse cabin walls is 1/3 to 1/4 of the ship length; the straight cabin walls are 1-2 meters closer to the a middle longitudinal cabin wall compared to an original side longitudinal cabin wall of the conventional floating production oil storage device; included angles between the oblique cabin walls and a ship length direction are 10-15 degrees. By adopting the fold-line cabin wall, the conventional ship concept is broken through; a fold-line cabin wall design is adopted, the cabin volume of an oil tank is reduced in the middle of the ship, and the volume of the oil tank is increased on the head and the tail parts of the ship, so that the structural weight distribution of the a ship body is changed, the weight of the middle of the ship is reduced, a sagging bending moment is lowered, the floating type oil production storage device is more reasonable in design, and the aims of lowering a still water bending moment and reducing the steel usage amount of the floating type oil production storage device can be fulfilled.