High photoluminescence (PL) quantum yield (QY), photostability CdSe@ZnS/ZnS core/multishell quantum dots (CM-QDs) were first applied for bioimaging. The solubility, stability and biocompatible of the fluorescence imaging probes were constructed by self-assembly of CM-QDs and pH-responsive methoxy poly(ethylene glycol)-poly(β-amino ester/amidoamine)-dodecylamine (mPEG-PAEA-DDA) multiblock copolymers. The resulting CM-QDs-loaded mPEG-PAEA-DDA micelles (CM-QDs-PEG-PAEA-DDA) exhibited lower cell cytotoxicity and higher fluorescence intensity than the core/shell CdSe@ZnS QDs-encapsulated mPEG-PAEA-DDA micelles (CS-QDs-PEG-PAEA-DDA). Moreover, the in vivo fluorescence imaging ability confirmed that the CM-QDs-PEG-PAEA-DDA can be employed as a pH-triggerable targeting imaging probe for detection of a rat bearing cerebral ischemia disease. Therefore, we believed that the CM-QDs-PEG-PAEA-DDA may be the next generation of fluorescence imaging probes for targeted diagnosis acidic pathological areas, using pH as a stimulus.