The invention discloses a gas discharge preionization apparatus. The gas discharge preionization apparatus comprises discharge electrodes, preionization needles, an insulation substrate, sealing rings, fixing nuts, plug-pull structures and peaking capacitors; the discharge electrodes and the preionization needles perpendicularly pass through the insulation substrate, and are fastened through the sealing rings and the fixing nuts to ensure a good vacuum sealing performance in a laser gas chamber; the preionization needles are uniformly on two sides of a discharge negative electrode along a length direction of the electrode; the two side faces of the electrode are processed to be sharp-edge-shaped, and preionization gaps are formed between the side faces of the electrode and the preionization needles; the preionization needles and the peaking capacitors arranged in the external of the gas chamber are communicated through the plug-pull structures to form a preionization charge and discharge loop; when the discharge electrodes are loaded with pulse high voltage, the preionization gaps are rapidly punctured to form arc discharge to radiate high-strength ultraviolet light to irradiate laser gas medium in the main electrode gaps to realize the ultraviolet light automatic preionization of the medium; since that the preionization needles and the discharge electrodes are positioned in the same plane, the preionization structures have no any influence on flow field structures of circulating gas, so that the gas discharge preionization apparatus is quite suitable for repetition frequency gas discharge lasers.