The invention discloses a semiconductor gas sensor array based exhaled air detection device which comprises an exhaled air collection module, a signal generation module, a signal processing module and a mode recognition module, wherein the exhaled air is subjected to thermal pretreatment and temperature and humidity detection and then subjected to quantitative collection; the exhaled air reacts with a gas sensitive film of the semiconductor gas sensor array with selectivity on air, so that the resistance change corresponds to voltage signal change; the signal processing module performs amplification, filtering and other processing on the voltage signal and performs analog/digital conversion; and the mode recognition module trains and recognizes the acquired data by using a mode recognition method. The device is capable of realizing synchronous analysis on multiple sensitive gases in the exhaled air, has the advantages of small size, low power consumption, high accuracy, real-time detection and the like and is applicable to medical aided diagnosis and healthy condition monitoring.