An assembling method for transportation of a cabinet, wherein the cabinet comprises a main cabinet and two side cabinets (1, 2), the respective side cabinet (1, 2) includes three entity surfaces, the three entity surfaces comprising a center surface and a top surface and a bottom surface extending from the center surface in a U-shape in a side view, the edges of the entity surfaces of the respective side cabinet defining a first and a second side of the respective side cabinet, and comprises a side door on the second side of the side cabinet, and a cabinet door, the side door and the cabinet door are detachable, the main cabinet comprises a post (203, 204) and a subrack, the main cabinet includes three entity surfaces with a backplane and a top surface and a bottom surface extending from the backplane in a U- shape in a side view, the edges of the entity surfaces of the main cabinet defining a first and a second side of the main cabinet, the two side cabinets (1, 2) are connected at their respective first side to the first and second side, respectively of the main cabinet, connections between the two side cabinets (1, 2) and the main cabinet are detachable, and the assembling method for cabinet transportation comprises: disassembling the connections between the two side cabinets (1, 2) and the main cabinet, wherein the disassembled main cabinet and the disassembled two side cabinets (1, 2) are independent of each other; disassembling the side doors and the cabinet doors from the two side cabinets (1, 2), wherein the side cabinet (1, 2) from which the side door and the cabinet door are disassembled is in its U- shape in the side view; placing side by side the two side cabinets (1, 2) from which the side doors and the cabinet doors are disassembled, such that a side of one side cabinet faces a side of the other side cabinet, and fixedly connecting the two side cabinets (1, 2) through a fixed connection apparatus; and buckling, with the main cabinet together in a staggered mode, the two fixedly connected side cabinets (1, 2) from which the side doors and the cabinet doors are disassembled wherein the U-shaped main cabinet is received in the U-shaped fixedly connected side cabinets (1,2). disassembling the connections between the two side cabinets (1, 2) and the main cabinet, wherein the disassembled main cabinet and the disassembled two side cabinets (1, 2) are independent of each other; disassembling the side doors and the cabinet doors from the two side cabinets (1, 2), wherein the side cabinet (1, 2) from which the side door and the cabinet door are disassembled is in its U- shape in the side view; placing side by side the two side cabinets (1, 2) from which the side doors and the cabinet doors are disassembled, such that a side of one side cabinet faces a side of the other side cabinet, and fixedly connecting the two side cabinets (1, 2) through a fixed connection apparatus; and buckling, with the main cabinet together in a staggered mode, the two fixedly connected side cabinets (1, 2) from which the side doors and the cabinet doors are disassembled wherein the U-shaped main cabinet is received in the U-shaped fixedly connected side cabinets (1,2).