Cancer imaging with minimal background signal and targeted intracellular drug delivery are of vital importance in clinical cancer diagnosis and therapy. Herein, we developed a biomimetic nanoprobe for activated fluorescence imaging and targeted drug delivery. pH-responsive porous coordination polymer nanoparticles (PCP NPs) were firstly synthesized by co-deposition method, anticancer drug doxorubicin (DOX) was then loaded into PCP NPs through physical and electrostatic adsorption (PCP-DOX), finally the cell membranes extracted from Bel-7402 cancer cells were coated on the DOX loaded PCP NPs (PCP-DOX-CM). The fluorescence of DOX was quenched due to the fluorescence resonance energy transfer between DOX and PCP NPs. Under acidic environment inside cancer cells, PCP NPs degraded, DOX was released from PCP-DOX-CM and the fluorescence of DOX was activated, which was very specific for cancers with high signal-to-noise ratio. Benefited from immune escaping and homologous targeting ability from cancer cell membranes, compared with PCP-CM and PCP-DOX, PCP-DOX-CM significantly enhanced the cellular endocytosis of DOX in Bel-7402 cancer cells and exhibited excellent cancer therapy effect in vitro. Together, our work provides a useful platform for activated cancer imaging system and personalized cancer treatment.