Beside cellular up-taking,the extremely low-efficient cytosolic release of the internalized siRNA has been concerned for intracellular siRNA delivery[1],and the early endosomal release was certificated an important issue for cytosolic siRNA delivery[2].Nowadays,advanced pH-sensitive vectors had been designed by combining several improvement components including the ultra pH-sensitive inner-core to enhance endosome release for high-efficiency siRNA delivery.However,there is still lake of clear idea about the rational design of siRNA vector to facilitate the cytosolic siRNA release mainly because high transfection efficiency is always companied with rather high uptake efficiency and it is hard to separate the contribution of cytosolic siRNA releasing on transfection efficiency from that of endocytosis[3].