Recently, plant-derived nanovesicles have attracted interest in the field of regenerative medicine because of their abundant immune-regulatory RNAs and phytochemicals with cell proliferation activity. However, the poor stability and rapid clearance of vesicles remain major challenges in their clinical applications. Herein, we report a facile method for surface modification of plant-derived nanovesicles by precipitation in the presence of poly(ethylene glycol) (PEG). We confirmed that PEGylation of nanovesicles slightly increased the particle size and zeta potential values. Importantly, this simple precipitation method produced PEGylated nanovesicles without any quantitative or qualitative loss of internal contents. When dispersed in PBS (pH 7.4), PEGylated nanovesicles did not exhibit a significant change in size for 24 h, indicating their high stability. Overall, our precipitation-based method is a useful technique for PEGylation of plant-derived nanovesicles without loss of bioactivity.