Abstract: To optimize regeneration and energy saving, the factors influencing the regeneration effect of 4A molecular sieve used in CNG deep dehydration were studied. Three groups of 4A molecular sieve samples with different adsorption level were collected, and each sample was divided into three groups, heated to 200℃, 240℃ and 260℃ for 9 hours, respectively. The desorption quantity of samples was measured, and the relation curves among heating time, regeneration temperature, and desorption quantity per unit mass (η) were calculated. The data showed that the suitable regeneration temperature of 4A molecular sieve was about 240℃, and the heating time was at least 3 hours. In order to evaluate the regeneration effect of molecular sieve, the regeneration temperature of CNG dehydration plant was risen from 200℃ to 240℃ with the same equipment and other operating parameters. The results indicated that the regeneration power consumption increased by 3.7 kW·h, but the heating time cut down by 1.5 h and the regeneration gas consumption decreased by 33.4 m³, the dehydration ability could be promoted from 18×10³ m³ to 22×10³ m³.