A patient support system, comprising: a patient support device comprising first air cells, second air cells disposed above the first air cells, and third air cells disposed above the first air cells; and an air distribution device, for connecting to an air supply source and the patient support device, the air distribution device comprising: a base comprising a first hole, a second hole, a third hole, an air supply hole and a deflation hole, the first hole for communicating with the first air cells, the second hole for communicating with the second air cells, the third hole for communicating with the third air cells, the air supply hole for communicating with the air supply source, and the deflation hole being for using in deflation; and an air distribution dial rotatably disposed on the base and comprising an air admitting portion, a deflation portion and a stop portion, characterized in that when the air distribution dial rotates to a first angle, the first hole, the second hole, and the third hole of the base come into communication with the air supply hole of the base through the air admitting portion of the air distribution dial, such that the first air cells, second air cells disposed above the first air cells, and third air cells disposed above the first air cells come into communication with each other, wherein, when the air distribution dial rotates to a second angle, the second hole of the base comes into communication with the deflation hole of the base through the deflation portion of the air distribution dial, and the stop portion of the air distribution dial covers the first hole of the base to prevent the first hole from coming into communication with any one of the second hole, the third hole, the air supply hole and the deflation hole, such that the first air cells in communication with the first hole are not in communication with the third air cells in communication with the third hole when the second air cells of the patient support device are deflated. a patient support device comprising first air cells, second air cells disposed above the first air cells, and third air cells disposed above the first air cells; and an air distribution device, for connecting to an air supply source and the patient support device, the air distribution device comprising: a base comprising a first hole, a second hole, a third hole, an air supply hole and a deflation hole, the first hole for communicating with the first air cells, the second hole for communicating with the second air cells, the third hole for communicating with the third air cells, the air supply hole for communicating with the air supply source, and the deflation hole being for using in deflation; and an air distribution dial rotatably disposed on the base and comprising an air admitting portion, a deflation portion and a stop portion, a base comprising a first hole, a second hole, a third hole, an air supply hole and a deflation hole, the first hole for communicating with the first air cells, the second hole for communicating with the second air cells, the third hole for communicating with the third air cells, the air supply hole for communicating with the air supply source, and the deflation hole being for using in deflation; and an air distribution dial rotatably disposed on the base and comprising an air admitting portion, a deflation portion and a stop portion, characterized in that when the air distribution dial rotates to a first angle, the first hole, the second hole, and the third hole of the base come into communication with the air supply hole of the base through the air admitting portion of the air distribution dial, such that the first air cells, second air cells disposed above the first air cells, and third air cells disposed above the first air cells come into communication with each other, wherein, when the air distribution dial rotates to a second angle, the second hole of the base comes into communication with the deflation hole of the base through the deflation portion of the air distribution dial, and the stop portion of the air distribution dial covers the first hole of the base to prevent the first hole from coming into communication with any one of the second hole, the third hole, the air supply hole and the deflation hole, such that the first air cells in communication with the first hole are not in communication with the third air cells in communication with the third hole when the second air cells of the patient support device are deflated.