Tight sandstone gas resource is an important unconventional petroleum resource. However the tight sandstone gas reservoir has disadvantages of small pore spaces, low porosity, low permeability, strong reforming effects by clay minerals, strong water wettability and low initial water saturation. During drilling and completion, it is likely to be damaged and hard to be cleaned up. The primary formation damages include solids plugging, sensitivity damages and water blocking due to aqueous phase invasion, and pressure sensitivity damage. Of all those damages, the damage due to aqueous phase invasion are more serious than solids invasion damage. Restricted by serious formation damages, conventional overbalanced or underbalanced mud drilling technologies have displayed poor effects, hard to conduct effective exploration and exploitation of tight sandstone gas reservoirs. Theoretic studies and field tests have shown gas drilling technology can exploit such gas reservoirs with high efficiency. Gas drilling can not only basically avoid the formation damages caused by invasion of drilling mud, but also can improve the drilling speed to a large extent, reduce drilling accidents, and shorten the time used for  well construction.