The invention discloses a printer negative-pressure system and a control method thereof. The printer negative-pressure system comprises a plurality of ink boxes, a body for accommodating the ink boxes and a stirring apparatus, wherein the body is divided into an upper layer and a lower layer, the upper layer of the body is provided with a plurality of spaces for accommodating the ink boxes, the lower layer of the body is used for storing the stirring apparatus, the stirring apparatus comprises a motor, a stirring impeller and a control circuit board, the control circuit board is electrically connected with the motor, and the motor drives the stirring impeller to rotate. According to the invention, the impeller is arranged in the ink boxes, ink in a head ink box is stirred by driving the impeller to rotate, the ink is effectively dispersed, and precipitation is prevented. According to the technical scheme, the system and method overcome the problem of precipitation of the ink in an ink supply pipeline and the head ink box by use of a conventional method and guarantee the quality of ink-jet ink.