The invention discloses a traffic flow running rate recognizing method based on bus GPS data and relates to a traffic information collecting and processing technology in the field of intelligent traffics. The method comprises the following solving steps of: carrying out grade division on an urban road section by a GIS; confirming a speed threshold value K1 and a speed threshold value K2 of all grades of roads; carrying out sub-road section division on the urban roads by the GIS; obtaining an average value of the speed that all buses pass through a sub-road section in a certain time interval, which is collected by a bus vehicle-mounted GPS system; comparing the average value of the speed with the threshold value K1 and the threshold value K2 of the sub-road section and confirming the traffic flow running rate of the sub-road section. The traffic flow running rate recognizing method based on bus GPS data can obviously improve the recognizing precision of the traffic flow running rate, reduce the time delay and provide the type of traffic jam simultaneously, thereby providing a basis for selecting more convenient traveling line for a traveler and proving more powerful decision support for establishing a jam facilitating scheme for a traffic management department.