The invention provides an over-ground height measuring method and device of a drone, the drone comprises a first sensor, the method comprises the steps: acquiring moving speed of the drone under a first coordination system by the first sensor; acquiring the moving speed of the drone under a second coordination system; determining the height of the drone relative to the ground according to the moving speed of the drone under the first coordination system and the moving speed of the drone under the second coordination system. Therefore, the height of the drone can be faster and relatively precisely measured by the first sensor.