Objective To explore the effect and mechanism of ivermectin (Ive) in enhancing oxaliplatin (L-OHP) against colon cancer HCT116/L-OHP cells. Methods In vitro establishment of colon cancer HCT116/L-OHP cells model with L-OHP low-concentration gradient increasing and low-concentration L-OHP (4 μmol/L) continuous culture. Set control group, L-OHP 25 μmol/L group, and L-OHP 25 μmol/L combined with 1, 2, 4, and 8 μmol/L Ive groups, and used MTT assay to detect cell viability. Set control group, L-OHP 25 μmol/L group, L-OHP+Ive 2 μmol/L group, and L-OHP+Ive 4 μmol/L group, and use cloning experiment to detect cell clone formation ability and flow cytometry apoptosis and cell cycle distribution, Western blotting was used to detect the expression levels of nuclear factor κB p65 (NF-κB p65), pregnane X receptor (PXR) and P-glycoprotein (P-gp). The colon cancer HCT116/L-OHP cells model with high expression of NF-κB p65 was constructed by LPS induction(setting control group, LPS group, LPS+L-OHP group, LPS+L-OHP+Ive 2 μmol/L group and LPS+L-OHP+Ive 4 μmol/L group), using lentiviral transfection to construct a colon cancer HCT116/L-OHP cells model with high PXR expression (setting control group, Ad-PXR group, Ad-PXR+L-OHP group, Ad-PXR+L-OHP+Ive 2 μmol/L group and Ad-PXR+L-OHP+Ive 4 μmol/L group), Western blotting was used to detect the expressions of NF-κB p65, PXR and P-gp protein levels. Twenty nude mice were injected subcutaneously with HCT116/L-OHP cells to establish a colon cancer drug-resistant cell transplantation tumor model and were divided into control group, L-OHP group, Ive group and Ive+L-OHP group, 5 mice in each group, and the tumor volume was calculated, the tumor weight was measured, and use immunohistochemistry to detect the expression of NF-κB p65, PXR and P-gp protein in the tumor tissues. Results Ive can potentiate L-OHP to inhibit colon cancer HCT116/L-OHP cells proliferation and clone formation (P<0.05), and promote colon cancer HCT116/L-OHP cells apoptosis and cell cycle S phase block (P<0.05).Western blotting showed that, in colon cancer HCT116/L-OHP cells, the expression levels of NF-κB p65, PXR and P-gp proteins in L-OHP+Ive 2 μmol/L group and L-OHP+Ive 4 μmol/L group were lower than those in control group, those in L-OHP+Ive 4 μmol/L group were lower than in L-OHP group (P<0.05). In the HCT116/L-OHP cells model with high NF-κB p65 expression, the expression levels of the NF-κB p65, PXR and P-gp protein in LPS+L-OHP+Ive 2 μmol/L group and the LPS+L-OHP+Ive 4 μmol/L group were lower than those in LPS group (P<0.05). In HCT116/L-OHP cells model with high PXR expression, the expression levels of the NF-κB p65, PXR and P-gp protein in Ad-PXR+L-OHP+Ive 2 μmol/L group and Ad-PXR+L-OHP+Ive 4 μmol/L group were lower than those in Ad-PXR group and Ad-PXR+L-OHP group, those in Ad-PXR+L-OHP+Ive 4 μmol/L group were lower than those in Ad-PXR+L-OHP+Ive 2 μmol/L group (P<0.05). In vivo experimental results showed that Ive can cooperate with L-OHP to inhibit the growth of HCT116/L-OHP cells xenograft tumors (P<0.05). The results of immunohistochemistry showed that the relative expression density of NF-κB p65, PXR and P-gp protein in the tumor tissues of Ive group, L-OHP group and Ive+L-OHP group was lower than that of control group. The L-OHP group and Ive+L-OHP group were lower than those in Ive group, and the Ive+L-OHP group were lower than those in L-OHP group (P<0.05). Conclusion Ive can enhance the effect of L-OHP against colon cancer HCT116/L-OHP cells, and its potential mechanism of action is to reduce the mediating effect of P-gp protein on L-OHP resistance by inhibiting the expression of NF-κB p65/PXR signaling pathway.