Abstract: The effective running of molecular sieve dehydrating unit is very important for natural gas processing. If molecular sieve dehydrating unit becomes invalid too quickly, it will restrict the safe, stale and effective operation of gas processing plant. The reasons for problems in molecular sieve dehydrating unit in the Dalaoba Gas Collection Station are discussed, and a series of practices are carried out. It has been found out that wax brought out by natural gas is harmful for molecular sieve’s efficiency. Some measures to improve the efficiency of molecular sieve dehydrating unit are proposed.