Passive defense system is composed of steel wire rope, steel Sige delete net. Bolt, beam column, the drop-down anchor rope, vacuum rings, bases and other components form the upper and lower support ropes. Rope system connected by a combination of steel columns and steel composition a whole area of the formation of protective surface protection, thereby preventing the collapse of the falling rock soil, slope protection played a role. SNS is characterized by passive protection system: the system flexibility and scattered field is strong enough to pass cut expected total impact energy rockfall washed, vacuum ring design and the use of impact the ability of the system be further improved. and steel retaining wall block, compared with the puzzle pulp: the change of the original construction process, schedule and funding to be reduced.