Objective:To investigate the in vitro anti-cancer effect of Vinorelbine (NVB) combined with adriamycin (PLD) on human breast cancer MCF-7 cells and related mechanisms.Methods:The effects of NVB and PLD alone or in combination on the proliferation of breast cancer cells were detected by CCK-8 experiment. Flow cytometry was used to detect cell apoptosis and changes in reactive oxygen species (ROS) levels. Western blot experiment was carried out to detect protein expression.Results:The results of CCK-8 showed that compared with the blank control group, the inhibition rates of the vinorelbine treatment group, the adriamycin treatment group and the combined treatment group were 27.6%, 31.2% and 65.4%, compared with the NVB group and PLD group, the difference between the combined treatment group was statistically significant ( P=0.005 vs 0.001) . The results of flow cytometry showed that the proportion of apoptotic cells in each group was 3.54%, 16.95%, 15.01% and 32.24%, compared with the NVB group and PLD group, the difference between the combined treatment group was statistically significant ( P=0.006 vs 0.005) . The levels of reactive oxygen species in each group were 1, 1.03, 1.06 and 1.57, compared with the NVB group and PLD group, the difference between the combined treatment group was statistically significant ( P=0.008 vs 0.007) . Western blot results showed that the expression of p-ERK and p-STAT3 decreased after the combination of NVB and PLD, which inhibited the ERK/STAT3 signaling pathway. Conclusions:The combination of NVB and PLD can promote the apoptosis of breast cancer cells and inhibit the proliferation of breast cancer cells with high efficiency and low toxicity. Its mechanism of action may be related to the up-regulation of ROS levels in cells, thereby inhibiting the activation of the ERK/STAT3 pathway.