In order to improve the apparent quality of electronic glass and reduce tin defects in glass, a new sealing method at the outlet of tin bath-gas seal was proposed. The effects of gas flow rate, gas pressure, height of gas seal structure from glass plate and pore structure on gas seal effect were studied respectively, and the parameters of the gas seal system were optimized. It was found that in a certain range, the gas seal effect became better with the increase of gas flow rate and gas pressure, and became worse with the increase of height of gas seal structure from glass plate, and the circular pore structure was better than the long pore structure in the outlet pore structure. The optimization of the gas sealing system effectively improves the apparent quality of float electronic glass and significantly reduces the occurrence of glass tin defects.