The invention provides a highway mileage stake number determining method based on an electronic map and a GPS coordinate. The method comprises the steps of S1, acquiring a certain highway segment through field acquisition equipment, performing matching with the electronic map according to a proportional relationship, acquiring a certain highway segment of another landform in a same manner, performing matching with the electronic map according to the proportional relationship, performing collection matching on highway segments in different types, and forming a highway segment database; S2, inputting to-be-matched vehicle information data into the database, and setting a GPS coordinate in a manner of calculating a target point, thereby obtaining a mileage stake number; S3, searching a corresponding highway segment through setting the GPS coordinate, and acquiring a matched highway segment name according to the GPS coordinate; and S4, after acquiring the highway segment name, determining a vehicle driving direction in a method of determining the direction according to the GPS coordinate, thereby finally determining the highway segment in which the vehicle exists and the driving direction.