Abstract: In this paper, the characteristics of the main dissolved salt elements and their contents in Terra-Cotta Warriors and Horses of Emperor Qin Shihuang Mausoleum Site were presented. Na2SO4 and NaCl are main deterioration salts, in addition, small amount of K and Ca sulfate and nitrate were also found. Amount of Mg sulfate was detected. The demage of Na2SO4 was very different from that of NaCl. Its super penetration, migration and destruction abilities led to much more serious demages, the salt demage styles were commonly salt efflorescence, falking and piece falling. The demage results of Na2SO4 salt were highly dependent on its containing temperature, the variation of environmental temperature and humidity. The easy demage condition regions are 32.4 ℃ and the humidity variation around 40%. The mimc of salt demage was carried out in the laboratory conditions, and the regualtions of salt migration was presented. The relatively permitted-critical relative temperature and humidity for the protection of the earthen sites are suggested. A starch grafted polyacrylamide superabsorbent material was used to remove the soluble salts. Very satisfied desalting results in Emperor Qin Shihuang Mausoleum Site were obtained.