The invention relates to a vehicle detection device based on a geomagnetic sensor array. The vehicle detection device based on a geomagnetic sensor array comprises a geomagnetic detection unit, a geomagnetic signal conditioning circuit, a data acquisition unit, a microprocessor, a memory cell and a wireless emission module. Changes of a magnetic field are caused because of disturbance of the surrounding magnetic field during the vehicle driving process can be detected by a plurality of geomagnetic sensors which are arranged in an array and are mounted in a vehicle detection device on the surface of a road on a lane line; a detection signal can be input into the microcontroller through the signal conditioning circuit; the microcontroller can process the geomagnetic data according to an interpolation method and a double-window vehicle detection algorithm so as to obtain the information of speed and length of a vehicle; and the information is input into the memory cell for storage, and can be sent through the wireless emission module. The vehicle detection device based on a geomagnetic sensor array utilizes a geomagnetic detection principle to detect vehicles, and is not influenced by weather factors, such as rain, snow and fog, and has the advantages of being abundant in the obtained traffic parameter information, avoiding damaging the road, being simple in installation and maintenance, being stable in operation, being small in volume, being low in cost, being low in power consumption, and being convenient for networking.