In this abstract, multifunctional Fe3O4@SiO2@PAA-cRGD nanocomposites were designed and synthesized to load water soluble Mn-porphyrin and anticancer drug doxorubicin, which could realize both pH-responsive drug release and T1/T2 dual-mode MRI capability. In vitro cell fluorescent imagings showed that c(RGDyk)-modified nanocomposites can effectively target A549 cells. Furthermore, in vitro T1-weighted and T2-weighted MR images of A549 cells were observed. For in vivo MRI, T1 and T2 relaxation was significantly accelerated in the tumor after i.v. injection of nanocomposites. These evidences showed that the nanocomposites could be used as pH-responsive T1/T2 dual-mode contrast agent, and have the potential for the tumor-targeted MRI and drug delivery.