The invention discloses a small unmanned aerial vehicle and ground end unidirectional wireless optical communication alignment tracking device and method, and belongs to the technical field of wireless optical communication. In the prior art, unidirectional wireless optical communication between a small unmanned aerial vehicle and a ground end has not been realized. The alignment tracking device in the invention comprises a ground end and an unmanned aerial vehicle end; the unmanned aerial vehicle end is carried by a small unmanned aerial vehicle; in the unmanned aerial vehicle end, an inertial sensor and an imaging optical system are mounted on a two-dimensional turntable; a tracking camera is installed at a focal plane of an imaging optical system; the inertial sensor and the tracking camera are respectively connected with a controller; the controller is respectively connected with the two-dimensional turntable and a radio frequency communication module; the imaging optical system isarranged on the two-dimensional turntable at the ground end; the tracking camera is installed at the focal plane of the imaging optical system; the tracking camera is connected with the controller; the controller is respectively connected with the two-dimensional turntable and the radio frequency communication module; and the light emitting direction of a tracking auxiliary light source faces theunmanned aerial vehicle end. The unmanned aerial vehicle end and the ground end are aligned with each other to track synchronously and dynamically; and tracking of each of the unmanned aerial vehicleend and the ground end comprises initial alignment, coarse tracking and fine tracking.