The invention discloses a method for reducing car tail gas and based on an intelligent dust-sucking type isolating fence. A plurality of automatic dedusting isolating fence units which are arranged between a plurality of lanes are included, every two automatic dedusting isolating fences are connected and fixed to form a large block of isolating fence; and two air inlets and at least an air outletare formed in the outer wall of each automatic dedusting isolating fence unit; the interior of each automatic dedusting isolating fence unit communicates with an air channel of the air inlets and thecorresponding air outlet, and filtering cloth bags are arranged in the air channels in a hanging state, and the air inlets face the filtering cloth bags. According to the method for reducing the car tail gas and based on the intelligent dust-sucking type isolating fence, by arranging the automatic dedusting isolating fence units between the multiple lanes, intelligent detecting and purifying of urban air is achieved, flying dust and haze are reduced, and more economical and energy-saving effects are achieved relative to a pure dedusting device.