This review provides an overview of biologically modified nanoparticles as theranostic bionanomaterials, which are anticipated to revolutionize the current theranostic modalities of diseases in the clinic and exhibit huge potential for further clinical applications. Display omitted Inspired by natural biology, cell membrane-mimetic surface engineering and cell membrane camouflaging technology have been widely investigated. Notably, the cell membrane-camouflaged nanoparticles (CM-NPs), which are produced by fusing synthetic nanoparticles with cellular membranes, gain unprecedented attention in biomedical fields. Compared with conventional nanosystems, these biomimetic nanoparticles (NPs) are bestowed with favored properties of elongated circulation time, immune evading and active targeting, which exhibit great potential in numerous biomedical applications and are anticipated to revolutionize the traditional nanomedicine. So far, a variety of cell membranes, along with expansive options of core materials, have been extensively investigated to construct the biomimetic system with unique functionalities. This review describes the evolution process from cell membrane-mimetic surface engineering to cell membrane camouflaging technology, which focuses on (I) cell membrane-mimetic surface engineering strategies (II) the fabrication of CM-NPs, (III) cell membrane-camouflaged nano-carriers, (VI) cell membrane camouflaged nano-phototherapeutic agents, (V) cell membrane camouflaged nano-antidotes, (VI) cell membrane camouflaged nanovaccines, (VII) cell membrane camouflaged nanoprobes, and (VIII) other relevant applications, providing an overview of the latest progress in the fabrication and application of cell membrane-based biomimetic and highlighting the major challenges as well as opportunities in this field.