The invention provides a variable-divergence-angle emission device of a wireless optical communication antenna. The optical axes of a fixed lens and a movable lens of a lens group are overlapped; initial state incident light is subjected to pre-collimation by the fixed lens and is subjected to complete collimation by the movable lens, and then, parallel light beams with the smallest divergence angle are output. A variable-divergence-angle structure component connects and controls the movable lens; the distance between the movable lens and the fixed lens is changed; lens group focus length and an output beam divergence angle are changed. The fixed lens is fixed in a fixed lens cone; a moving lens tube fixing the movable lens is nested in the fixed lens cone; a motor of a variable-divergence-angle structure drives the movable lens tube to axially move through a gear, a rotating tube and a guide rod. The variable-divergence-angle emission device has the advantages that the structure is simple; the cost performance is high; the reliability is high; the position of a laser source or the distance between the laser source and an optical system does not need to be changed; the change of the emitting beam divergence angle can be regulated only through changing the distance between the fixed lens and the movable lens, so that the influence of the divergence angle regulation on the parallel degree between all device emitting optical axes of all devices and between receiving optical axes of the all devices can be ignored.