The invention discloses a distributed low temperature wind tunnel air exhausting system and belongs to the technical field of wind tunnel air exhausting. The air exhausting system comprises an air exhausting master pipe connected with an outlet of a low temperature wind tunnel, an air exhausting branch pipe arranged on an air exhausting end of the air exhausting master pipe, and mixed air exhausting units installed at all air exhausting outlets of the air exhausting branch pipe, wherein the air exhausting branch pipe is provided with a number of upward air exhausting outlets arranged along a length direction, the mixed air exhausting units comprise vertically arranged mixed flow passageways with upper and lower openings, the air exhausting branch pipe runs through the mixed flow passageways while the air exhausting outlets are positioned in the mixed flow passageways, a fan used for blowing air into each mixed flow passageways to expedite mixing of nitrogen and air is arranged blow each inlet of the mixed flow passageways, and an atomizer used for spraying atomized water mist upward is arranged below each air inlet. A large amount of low temperature nitrogen output from the low temperature wind tunnel is dispersed to all the mixed air exhausting units via the air exhausting branch pipe, low temperature nitrogen which is originally exhausted in a concentrated manner is dispersedinto a plurality of small airflows, air is blown into the mixed flow passageways via fans and is mixed with the low temperature nitrogen, and temperature of the low temperature nitrogen is increasedvia atomized water mist sprayed from atomizers.