The invention relates to a side-opened package box for transporting the whole satellite or a satellite cabin and belongs to the technical field of satellites. The package box mainly adopts a side-opened structure and comprises a box body, a box door, and a door open / shut mechanism. A guide rail A is arranged on the inner side of the box door and a guide rail B is arranged on the bottom surface of the box body. When the box door is opened, the guide rail A on the inner side of the box door and the guide rail B on the bottom surface of the box body are positioned on the same plane and can realize seamless connection through a transitional guide rail C; and after the box door is opened, a sliding trolley can freely slide on a horizontal guide rail formed by the guide rails A, B, and C. The door open / shut mechanism comprises a pulley block, a rocking handle, a reducer, and a cable wire, wherein the pulley block is mounted on the top surface of the box body, the reducer is mounted on a lateral surface of the box body, the rocking handle is mounted on the reducer, and the cable wire is connected with the reducer, the pulley block, and the box door sequentially. The invention has the advantages that no hoist is needed, the requirement on operation spaces in factory buildings is low, and the satellites can be taken into and out of the box conveniently, safely, and reliably.