ince Nanba cryogenic plant starts up production at its early stages, several problems have been found about molecular sieve dehydration units, such as the pressure of molecular sieve beds increases or reduces too quickly; the designed regeneration temperatures are not up to standard; the adsorption/regeneration period is unreasonable; the control program is not perfect. Then through theoretical analysis and on-site test, we optimizes the dehydration system, thus the pressure increase/decrease rate is adjusted from 0.73MPa/min to 0.25MPa/min and the temperature of hot blowing is adjusted from 180℃ to 210℃, and the adsorption/regeneration period is regulated from 8 hours to 12 hours as well. Meanwhile, during the pressure increasing/reducing of molecular sieve beds, the program will be enforced automatically with feedback confirmation to avoid misoperation. Finally, through these improvements, the above problems are effectively solved, ensuring the good running of the molecular sieve dehydration system.