The utility model relates to a motor-vehicle type identifier, which is composed of a sensor whose output is connected with an interface control circuit whose output is connected with an existing computer, wherein, the interface control circuit is connected with the input terminal of a CPU through a signal processing circuit; an interface wire of the CPU is connected with a data register which is connected with an input-output bus line of a microcomputer; the sensor is an annular inductive coil which is pre-embedded on a highway. The utility model is characterized in that the variation of coil inductance is reflected by the variation of an oscillating circuit converting to frequency; coil frequency values of each moment are described to obtain a frequency curve of a vehicle passing through an annular coil which can be used for detecting and classifying vehicles.