Abstract：Objective To prepare raltitrexed pH-sensitive liposomes, optimize their formulation and preparation process, and evaluate the optimized pH-sensitive liposomes. Methods Single factor investigation and orthogonal optimization were performed to optimize the prescription. In addition, the particle sizes, zeta potential, encapsulation efficiency, in vitro release, and cytotoxicity of the raltitrexed pH-sensitive liposomes prepared by the optimal prescription were studied. Results The raltitrexed pH-sensitive liposomes prepared according to the optimal prescription had average particle sizes of (227.0±21.4)nm, a PDI of (0.223±0.061), a Zeta potential of (-44.2±3.6)mV, and an entrapment efficiency of (58.3±2.1)%. It was shown that drug-loaded liposomes released faster in the release medium of pH5.0 and pH6.0 compare to the pH of 7.4. Cytotoxicity test confirmed that the liposome carrier itself was safer and the drug-loaded liposome has higher cytotoxicity. Conclusion In conclusion, results showed that the optimized raltitrexed pH-sensitive liposome had a simple preparation method, suitable physiochemical properties, high safety, and had broad clinical application prospects.