The invention relates to a survey system for measuring the grain yield of a wheat field by means of an unmanned aerial vehicle on the basis of Beidou navigation, and belongs to the new technical fieldof grain yield survey. A Beidou satellite emits a Beidou signal, an airborne mobile reference station in an unmanned aerial vehicle body, a mobile reference station installed at the left side of thewheat field and a fixed reference station installed at the right side of the wheat field form an air-land combined reference station enhancement system information sent by each reference station enhances the Beidou signal for navigation and positioning, and therefore a Beidou satellite user terminal additionally installed in a wheat yield measuring center obtains yield measuring area data high inpositioning precision. A big data acquisition device of the unmanned aerial vehicle scans, counts and records ears in an image and sends obtained information about the number of ears per mu and the number of ear grains to the wheat yield measuring center, a wheat test chamber sends thousand grain weight data of wheat to the wheat yield measuring center, and a third electronic computer in the wheatyield measuring center calculates the wheat yield according to the the number of the ears per mu, the number of the ear grains and the thousand grain weight data and sends the wheat yield to a wheatyield survey station.