Abstract：Sr-Nd isotopic data of the Jurassic granites in northeastern Da Hinggan Mountains show that Xing’an massif has relatively low initial Sr (0.7048~0.7065) , high εNd(t) (+0.23~+2.54), and low TDM2(0.76~0.95 Ga), suggesting that their source materials were mainly crustal materials derived from the depleted mantle during Phanerozoic. In contrast, Jurassic granites in Ergun massif have relatively high initial Sr (0.7057~0.7075), low εNd(t)(-2.47~-9.72), and high TDM2 (1.16~1.7 Ga), implying that their source materials were mainly crustal materials derived from the depleted mantle in Meso-Neo-Proterozoic. Different crustal accretion periods of Ergun and Xing’an massifs suggest they have different early crustal evolution histories.