Cancer cell-targeted imaging and drug delivery remain a challenge for precise cancer theranostics. MUC1 is a large transmembrane glycoprotein that may potentially serve as a target for cancer theranostics. Herein, using a MUC1-targeting aptamer (APT) as the “warhead”, we rationally designed and constructed a hybrid nanoparticle 1-NPs-QDs-hAPT (Vehicle) that could be applied for MUC1-targeted cell uptake and imaging. By intercalating different Vehicle amounts with the anticancer drug doxorubicin (DOX), we obtained the multifunctional bioconjugate Vehicle-DOX with a maximized drug payload and DOX fluorescence quenching capability. Confocal microscopy cell imaging indicated that Vehicle-DOX could be used to track MUC1-targeted drug release. A cytotoxicity study indicated that Vehicle-DOX could be applied for MUC1-targeted cytotoxicity. We anticipate that our multifunctional bioconjugate Vehicle-DOX could be applied for in vivo tumor-targeted theranostics.