The invention discloses an indoor air quality diagnosing system based on a robot. The indoor air quality diagnosing system mainly comprises a first sensor, a second sensor, a third sensor, a fourth sensor, a robot controller and a robot displayer, wherein the first sensor, the second sensor, the third sensor and the fourth sensor are separately used for collecting the indoor temperature, the air humidity, the air velocity and the air chemical component information; the information is transmitted to the robot controller to be processed, and the data are displayed through the robot display device; thus, the advantages of being simple in structure, accurate in diagnosing results and easy to achieve are obtained.