The invention relates to a central air supply, heat dissipation and noise reduction system for a motor group. The central air supply, heat dissipation and noise reduction system for the motor group comprises motors, noise reduction rooms, draught fans and air pipes, wherein the noise reduction rooms are arranged in a factory or each workshop, the draught fans which are used for centrally supplying air are installed in the noise reduction rooms, the wall, corresponding to an air outlet of each draught fan, of each noise reduction room is provided with a ventilation opening, the ventilation opening is communicated with a main air pipe arranged on a support in a suspended mode, a plurality of branch air pipes are distributed and arranged on the main air pipe, and the air outlet of each branch air pipe is communicated with the air inlet formed in each fan housing of the motor respectively. The central air supply, heat dissipation and noise reduction system for the motor group has the advantages of being suitable for the central air supply, heat dissipation and noise reduction for the motor group, capable of effectively improving the cooling and heat dissipation effects of the motor, obvious in noise reduction effect, and capable of enabling the noise of the motor group in operation to be meet the requirement of being less than or equal to 85dB (A). The utilized air pipes are all flexible air pipes which are made of fiber fabric to supply the air, the cost is greatly lowered, the air supply effect can be fully met, and the energy-saving effect is remarkable.