Characteristics of charge fingerprint and its contributing factors of soils on the Wuzhi Mountain in Hainan Island were studied.The results illustrated that charge fingerprint of the soils decreased with pH (7.0,6.4,5.8,5.2,4.6,4.0);and it was significantly correlated with soil organic matter,pH,clay content,exchangeable hydrogen and exchangeable aluminum.Regression analysis found that clay content was more important in the situation of low pH for conservation of soil nutrients.Charge fingerprint could be calculated based on some conventional physio-chemical indexes,such as soil organic matter,pH,clay content,exchangeable hydrogen,exchangeable aluminum,etc.and it could be used as a major index to assess nutrient holding capacity and predict potential impact of soil acidification on nutrient loss.