Air duct system of sleeping berth motor train unit

The invention provides an air duct system of a sleeping berth motor train unit. The air duct system comprises air filtration devices, mixed air boxes, an air conditioning unit, a main air duct, branch air ducts, compartment air ducts and compartment air supply ports, all of which are communicated in sequence. The air duct system further comprises a waste discharge device. The waste discharge device is used for discharging waste gas in the motor train unit. The main air duct is arranged at the top of the motor train unit in the longitudinal direction of the motor train unit. The branch air ducts are arranged on the two sides of the main air duct. Each compartment air duct comprises a compartment upper berth air duct, a compartment lower berth air duct and a compartment cross wall air duct, the compartment upper berth air ducts and the compartment cross wall air ducts are communicated with the branch air ducts, and the compartment lower berth air ducts are communicated with the compartment cross wall air ducts.