The invention discloses a molecular sieve dehydrating system and technology which are applied to the field of natural gas treatment. The system comprises a raw material gas filtering device, a raw material gas heat exchange device, at least three dehydrating towers which are in parallel connection, a dust filtering device, a regenerated gas heating furnace, a first cold blown gas/regenerated gas heat exchange device, a second cold blown gas/regenerated gas heat exchange device, a regenerated gas gas cooling device, a regenerated gas separation device, a cooling device filtering device and a regenerated gas filtering device. According to the system, by arranging the regenerated gas/cold blown gas heat exchange device at an outlet of the regenerated gas heating furnace, the regeneration process of a molecular sieve and the steady temperature change in the cooling process of the dehydrating device can be achieved, a gas source is adopted by the cooling gas blowing adopted in the cooling process and regenerated gas in the regeneration process, the gas source is firstly used for cold blown gas and then used for gas regenerating, the using amount of the regenerating amount is reduced, the second cold blown gas/regenerating gas heat exchange device is arranged at an outlet where the cold blown gas leaves the absorbing tower, and therefore the consuming amount of fuel gas in a regenerated gas heating furnace is reduced.