The invention provides a mute air-cooled generating set which comprises a chassis and a soundproof box. An engine and a generator coaxially connected with the engine are arranged in a space formed by the surrounding of the soundproof box and the chassis; the soundproof box and/or the chassis is provided with an air port; an exhaust fan coaxially connected with a flywheel is arranged at one side of the flywheel of the engine; the exhaust fan is covered with an exhaust wind scooper; an air inlet of the exhaust wind scooper is positioned in the soundproof box; an air outlet of the exhaust wind scooper is communicated with an exhaust chamber; the exhaust chamber is communicated with the atmosphere outside the soundproof box. When the mute air-cooled generating set operates, gas in the soundproof box is constantly extracted by the exhaust fan, is led into the exhaust chamber and is discharged into the atmosphere from air outlets on the periphery of the exhaust chamber, at the moment, hot gas in the soundproof box is exhausted, the gas pressure is reduced, cold air outside the soundproof box can be continuously supplemented into the soundproof box through air inlets preset on the soundproof box or the chassis so as to form a circular cooling system, thereby effectively reducing the temperature in the soundproof box.