OBJECTIVE To characterize paclitaxel nanoparticles （PTX-PLGA-NPs） and evaluate their in vitro inhibitory effect on Lewis lung cancer cells. METHODS The PTX-PLGA-NPs prepared by the emulsion-solvent evaporation method were characterized in terms of particle size， polydispersity index （PDI）， Zeta potential， microscopic morphology， encapsulation efficiency， drug loading， ultraviolet-visible absorption characteristics and stability. Using mouse Lewis lung cancer cells as the subjects and paclitaxel reference substance as the control， the cytotoxicity and in vitro killing activity of PTX-PLGA-NPs were detected using CCK-8 method and Calcein-AM/PI double staining method， respectively. The effects of PTX-PLGA-NPs on cell apoptosis and cell cycle were assessed by Annexin Ⅴ-FITC/PI staining method and PI staining method， respectively. RESULTS PTX-PLGA-NPs were spherical with an average particle size of （172.03±0.95） nm， PDI of 0.098±0.012， and Zeta potential of （－1.76±0.02） mV. The encapsulation efficiency and drug loading were （52.32±0.66）% and （7.07±0.18）%， respectively， and the ultraviolet-visible absorption characteristics were not affected by the carrier polylactic-co-glycolic acid. When stored in the dark at 4 °C for 7 days， no significant change was noted in particle size， and the average PDI （after 1， 2， 4 and 7 days of storage） was under 0.3. Compared with the paclitaxel reference substance group， the PTX-PLGA-NPs group had more cells in a state of death， the survival rate （at the PTX concentration of 11.2 μg/mL） was significantly decreased， and both the apoptosis rate and the proportion of G2 phase cells were significantly increased （P＜0.05）. CONCLUSIONS The prepared PTX-PLGA-NPs indicate homogeneity in particle size， uniform dispersion， stable properties， and stronger in vitro killing effect on lung cancer cells than PTX.