The granitoids broadly distributed in eastern Jilin and Heilongjiang have long formation history and complete types. Genetically, the granites are mainly of I-type, with subordinate A-type, minor S-type and rare M-type. The stable isotope compositions of most rock bodies are characterized by low initial Rb-Sr values, normal or lower oxygen isotope values, low204Pb , high206Pb/204 P, 207Pb/204 Pb and 208 Pb/ 204 Pb ratios, and high Nd initial values. These features show that, mixed with much mantle material, the basement rock has low maturity. These characteristics are obviously different from those of the granites in North and South China.