Nd-Sr isotopic compositions for 20 granitoid bodies of syntexis series in South China have been studied in this paper. Based on the isotopic com positions of samples and their distribution characteristics on the €Nd-T,(87Sr/86Sr)-T, €Nd-Єsr,diagra ms, these granitoids of syntexis serves are considered as mixing products of upper crust end-member and depleted mantle end-member in certain proportion. Crust-mantle mixing proportions of these granitoids are calculated by using the two-component mixing equations. According to tectonic environments and material sources, granitoids of syntexis series in South China can be divided into three types: the continental margin type,the continental interior type, and the fault depression zone type.