The invention discloses an unmanned plane flight track precision detection method and a device. The method comprises steps that, a three-dimensional flight track of an unmanned plane is acquired through an airborne differential GPS unit of the unmanned plane in real time, and a preset three-dimensional flight track of the unmanned plane is acquired; distances from at least three detection radars of a radar detection unit to the unmanned plane are measured in real time, and at least three distance values are acquired; an actual three-dimensional flight track of the unmanned plane is acquired according to the at least three distance values; a three-dimensional precise flight track evaluation parameter of the unmanned plane can be calculated according to the preset three-dimensional flight track and the actual three-dimensional flight track. According to the method, three-dimensional positioning of the unmanned plane can be realized through the additional detection radars, high precision positioning on the actual flight track of the unmanned plane can be realized, through analysis comparison with the three-dimensional flight track of the unmanned plane through differential GPS detection, three-dimensional flight track precision of the unmanned plane can be acquired, and high-precision positioning on the actual flight track of the unmanned plane can be realized.