The invention relates to a linked landing gear cabin door folding and unfolding device and belongs to the technical field of aircraft manufacturing. The linked landing gear cabin door folding and unfolding device comprises a landing gear, a rotation shaft I, a rotation shaft II, a rotation shaft III, a rotation shaft IV, an upper supporting rod, a rocker arm I, a rocker arm II, a rocker arm III, a lower supporting rod, a folding and unfolding actuation cylinder, a connection rod I, a connection rod II, a connection rod III, a goose-shaped rocker arm, a support column protection plate and an airplane wheel protection plate. By virtue of the linked landing gear cabin door folding and unfolding device, the cabin door folding and unfolding actuation system is simplified, so that the occupying space of the device in an airplane is reduced and the structure weight is reduced; by virtue of the design of a linked mechanism, the order of folding and unfolding the landing gear, the airplane wheel protection plate and the support column protection plate is ensured, the control logic is simplified and the reliability is improved; the airplane protection plate is closed when the landing gear is unfolded, the pneumatic resistance can be reduced; the takeoff and landing performances of the airplane are improved; the damage to the airplane, caused by entrance of foreign materials in a landing gear cabin, can be avoided.