The invention provides a PC host dedusting box having high dedusting efficiency. A dust falling bin communicates with a dedusting box and a compression fan correspondingly; an air outlet is arranged on the compression fan; universal wheels are arranged at the lower end of the dust falling bin; a dedusting cavity is formed in the dedusting box; a door sheet is arranged on one side of the dedustingbox; a handle is arranged on the door sheet; the door sheet is rotatably mounted on the dedusting cavity through hinges; the dedusting box is provided with a mounting plate in a horizontally extendingmanner from inside to outside; a sliding groove is formed in the mounting plate; pulleys are arranged in the sliding groove; a bearing plate is mounted on the pulleys; a limiting plate is mounted onthe bearing plate; a push rod is arranged on the limiting plate; a first blower is arranged at the position, located above the mounting plate, in the dedusting cavity; a first spray head mounting seatis arranged on the first blower; a first spray head is arranged on the first spray head mounting seat; a first transmission channel is connected between the dedusting cavity and a dust collecting cavity; and the dust collecting cavity communicates with the compression fan through a filter screen. The PC host dedusting box can avoid raised dust in the PC machine dedusting process and the PC host dedusting efficiency and quality are improved.