The invention relates to an electro-optic Q switch, which comprises an electro-optic crystal, a shell, gold wires, electrodes and leads. The shell consists of a base, a bracket and two side covers, wherein the bracket is a rectangular frame with front and rear panels; the base has a convex shape; the frame is fixed on the base; an upper cover is arranged on the top of the bracket; a flexible glueinjection hole is formed on the frame; and transmission holes are formed on the front and rear panels. A longitudinal axis of the electro-optic crystal is parallel to that of the base and is fixed onthe top of the base; a first electrode and a second electrode are formed on two protruding outer side walls of the base; gold-plated surfaces are formed on two side surfaces of the electro-optic crystal; a first group of gold wires and a second group of gold wires are connected between the gold-plated surfaces and the first and second electrodes; a first lead and a second lead are respectively welded at the other ends of the first and second electrodes; and the other ends of the first and second leads respectively penetrate the first and second side covers to be electrically with an external power supply. The electro-optic Q switch reduces the stress of an electro-optic Q crystal to the greatest degree.