To explore targeting stromal cell-derived factor-1 (SDF-1) to enhance colorectal cancer (CRC) chemotherapy sensitivity by regulating the transformation of tumor-associated macrophages (TAMs) subtypes. Methods THP-1 cells were induced into TAMs cells with PMA and IL-4 in vitro. Flow cytometry was used to detect the expression of M1/M2 specific surface markers CD86 and CD206. TAMs cells were treated with 5 μg/mL SDF-1 inhibitor AMD3100 for 24 h. The expression of SDF-1 was detected by quantitative real-time PCR (qRT-PCR) and Western blot. The expressions of iNOS, TNF-α, TGF-β and Arg-1 were detected with qRT-PCR. The co-culture system of human colorectal cancer cells LoVo and TAMs cells was established, and LoVo cells were treated with different concentrations of 0, 0.5, 5, 50, 500 μmol/L oxaliplatin. The specific groups included blank control group, oxaliplatin group, TAMs+ oxaliplatin group, and AMD3100+TAMs+ oxaliplatin group. The cell viability of LoVo was detected with CCK-8. The animal colorectal cancer xenograft model were constructed. After being tumors grow choose tumor size of 100 mm 3 of 12 nude mice, according to random number table method is divided into control group, group, AMD3100 oxaliplatin into plus oxaliplatin into groups, each group of four. The oxaliplatin group was intraperitoneally injected with 8 mg/kg oxaliplatin, the AMD3100+ oxaliplatin group was intraperitoneally injected with 5 mg/kg SDF-1 inhibitor AMD3100 and 8 mg/kg oxaliplatin, and the control group was injected with the same volume of normal saline once a day for 18 days. Tumor volume was measured at 0, 3, 6, 9, 12, 15 and 18 days after the first dose. Tumor tissue was dissected and weighed at 18 days, and tumor tissue suspension was prepared. M1/M2 macrophages were sorted by flow cytometry, and the expressions of iNOS and Arg-1 were detected by immunohistochemical staining. Results TAMs cells were successfully induced in vitro. After treatment with SDF-1 inhibitor AMD3100, the expression levels of SDF-1 on mRNA and protein in TAMs cells were down-regulated, the relative mRNA expression of iNOS and TNF-α increased, the relative mRNA expression of TGF-β and Arg-1 mRNA decreased (P＜0.01). The survival rate of LoVo cells decreased after 0.5, 5, 50, 500 μmol/L oxaliplatin treatment, after co-cultivation with TAMs and treatment with oxaliplatin, the survival rate of LoVo cells increased, However, the survival rate of LoVo cells decreased after being co-cultured with TAMs treated with SDF-1 inhibitor AMD3100 and then treated with oxaliplatin (P＜0.01). The tumor tissue growth of the transplanted tumor nude mice treated with oxaliplatin slowed down and the tumor weight decreased, the tumor tissue growth of the transplanted tumor nude mice treated with the SDF-1 inhibitor AMD3100 and oxaliplatin combined treatment further slowed down and the tumor weight decreased, at the same time, F4/80+CD11c+ expression in tumor tissues increased, iNOS expression increased, F4/80+CD206+ expression decreased, and Arg-1 expression also decreased. Conclusion Targeting SDF-1 by the SDF-1 inhibitor AMD3100 can enhance the chemotherapeutic sensitivity of colorectal cancer in vitro and in vivo, and its mechanism of action may be related to the regulation of tumor-associated macrophage M1/M2 subtype transformation.