The water content of mainstream smoke components is closely associated with the sensory comfort of smoking, and it was also susceptible to the environment. In order to improve the stability of the water content in cigarette tobacco, the effective two-way water-blocking additive was developed of aliphatic hydrocarbons and compound sugars, the synergy of both additives made the water content of tobacco under a good control. The function of the additive was proved by testing in the simulation environment (RH=32% and RH=84%) in 35 ℃. Finally, proved that when added 1.0% aliphatic hydrocarbon (GY) and 0.1% polysaccharose (B), a good two-way water blocking effect can be achieved, effectively delaying either the tobacco moisture absorption or desorption time. Through using the environmental scanning electron microscopy (ESEM), studied the surface of the tobacco and found the coating material isolating the tobacco from the environment, which would be a convincing evidence to show the additive does work.