In this report, several methods have been provided to investigate the possibility of a long‐term sealed‐off operation of a CW transversely‐excited (TE) CO2laser. These methods include the additions of molecular 3A sieve, CO gas, auxiliary discharge, and catalysts. Variations of gas composition, discharge voltage, and laser power under different conditions have been analyzed. SnO2coating devices and monolithic catalysts have been introduced for the first time in a CW TE CO2laser. With an appropriate amount of these catalysts, sealed‐off operation with an output level at 550W for more than 110 Hours of discharge time was achieved.