The invention relates to a system rapidly detecting the influence of motor vehicle to atmospheric PM2.5, and an operation method thereof. The system is composed of a data processing module, a PM2.5 processing module, a vehicle road occupation time processing module, a PM2.5 sampling module, and a vehicle sensor module. Monitoring and sampling analysis are carried out upon vehicle operation state through the vehicle sensor module and the vehicle road occupation time processing module; Atmospheric pollution degree is sampled and analyzed through the PM2.5 sampling module and the PM2.5 processing module; a relationship curve of the vehicle operation state and the atmospheric pollution degree is displayed in a form of a chart or a table by the data processing module, and alarming is carried out when a state exceeding a preset pollution index level is detected. With the system and method provided by the invention, the influence degree of PM2.5 in exhaust gas emitted during motor vehicle operation upon a current atmosphere actual PM2.5 content value can be quantitatively obtained. Therefore, a real cause of exceeded atmospheric PM2.5 content can be obtained by a decision maker, and atmospheric PM2.5 content exceeding can be controlled and treated with targeted measures.