The invention discloses a building wall heat, humidity and air coupling transmission characteristic testing device and method and belongs to a building wall heat and humidity coupling transmission testing device and method. A static pressure box with an opening formed in one side is installed on one side of a tested building wall in a sealed mode, an air inlet of the static pressure box is flexibly connected with an air outlet of a draught fan, temperature and humidity sensors are arranged in a wall and on the surface of the other side of the wall, a temperature, humidity and pressure sensor is arranged in the static pressure box, and temperature, humidity and pressure signals are transmitted to an acquisition module which is connected with a computer through a signal transmission line. Air ports of the static pressure box include adjustable air outlets and the air inlet provided with a multi-blade adjusting valve. Temperature, humidity and air pressure are transmitted to the computer through the acquisition module, and the temperature and humidity distribution condition in the wall under different pressure differences is displayed, stored, recorded and monitored through online monitoring software. The method is easy and convenient to execute, testing accuracy is high, the method can be widely used for measuring the temperature and humidity field distribution of the building wall in the heat, humidity and air multi-field coupled transmission process.