Human mesenchymal stem cell-derived small extracellular vesicles(MSC-sEVs) have exhibited immunomodulatory and pro-regenerative properties. However, the absence of quantifiable and specific markers for defining and qualifying human MSC-sEVs impedes their translation into clinical practice. Here, we ranked the relative abundances of proteins representing unique signature for MSCs in the proteomic datasets of MSC-sEVs and chose several proteins with high relative abundances as candidate markers for MSC-sEVs. This work would facilitate the establishment of quantifiable, reproducible and standardized assays for defining MSC-sEV preparations, ultimately accelerating the translation of MSC-sEVs into clinical practice.