In conclusion, this study successfully developed P123-PEG2000-DSPE (Dox), and P123-PEG2000-DSPE (Dox) had a superior anti-tumor activity than PEG2000-DSPE (Dox) in MCF-7R cells by reversing MDR based on P-gp-mediated drug excretion and drug resistance mechanisms. The gene discussed is PGP; the disease is neoplasm.