Abundant strontium isotopic data have been accumulated in the studies of the Circum-Pacific belt of continental volcanic rocks in eastern China; inclu- ding the work done by the author of this paper. Among the data. there are 15 initial ratios determined by ftb-Sr isochron method. The Jurassic volcanic rocks of western Liaoning and eastern Jilin Province and the Mfiddle Jurassic granite of Fujian Province have similar initial 87Sr/86Sr ratios in the range of 0.7050-0.7060. The initial 87Sr/86Sr ratios obtained from andesites and rhyo- lites. of 145-137Ma (referred to Late Jurassic in current stratigraphical time- table) in Yen-Liao region fall in the range of 0.706-0.709. The seven intitate ratios of the volcanic rocks of the Jiande Group in Fujian-Zhejiang region are 0.7067一0.7089, most of the samples for dating being collected from rhyo- lites. Based on the available data, the initial 87Sr/gsSr ratios of the igneous rocks older than 140Ma (i. e., Jurassic volcanic rocks and granites) are less than 0.706 whereas the initial ratios of the Cretaceous volcanic rocks are greater .than 0:706. The Early Cretaceous acidic volcanic rocks have initiate 87Sr/86Sr ratios of 0.707-0.709. This is obviously higher than that of basic rocks. The difference、of these two values are between 0.002-0.003. The contamina- tion of magma can be recognized merely from the comparison of the two values. The present data show that the initial 87Sr/86Sr ratios of the volcanic belt are in the range of 0.705-0.709. Howevea, all the high values are obta- fined from the acidic rocks which are prone to contamination. So, the value of 0.705士0.001 may be taken as the possible range of the iinitial ratios of the parent magma. Based on the fact that both the present ratios of 0.705- 0.709 and the inferred ratio of the parent magma (0.704-0.706) fall in a narrow range, the volcanic roclcs studied may be regarded as a type of rock between island-arc andesites and continental-volcanics. The are quite similar to rocks of the typical rift type (such as those in Oslo amd western Africa). This suggests tliat a mechanism similar to rif ting possibly existed at the eastern margin of China mainlapd during 240-95Ma B.P.as a result of the interaction between the Pacific plate and the Eurasian plate.