Abstract: We compared morphological characters , phenology and chemical elemental content s of seven threatened plant species in limestone soil with those in acid red soil. The results show that the following variations occurred after the plants had been introduced to acid soil : 1) the leaves became larger and thinner , and the seeds and leaf shape of some species changed ; 2) the flowering , fruit bearing and leaf falling was delayed one week ;3) the chemical content of N , Zn , Band Al increased as much as 20 % , but Ca decreased by 10 % , though much higher than those in acid soil ; 5) the K, B absorbencies of the plants in limestone soil were about 10 %;4) the content of Ca decreased , but was still much higher than the plants in acid soil. The content of Al higher than those in acid soil , but the absorbencies of other elements (N , P , Ca , Mg , Fe , Al , Mn and Zn) were lower than those in acid soil.