Aim To explore the role of C-X-C motif chemokine receptor 4 (CXCR4) in the formation of atherosclerosis (As) induced by Chlamydia pneumoniae (C.pn) infection. Methods The As model in mice of ApoE－/－, ApoE－/－＋TLR2－/－ and ApoE－/－＋Toll-like receptor 2 (TLR2)－/－＋AMD3100 induced by C.pn infection was established on the basis of high fat diet. C.pn IgG and IgM antibody levels were detected by ELISA, and C.pn specific DNA was detected by PCR. Lipid deposition and As lesion area in aorta and aortic root were observed by oil red O and HE staining. Serum levels of total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDLC) and high density lipoprotein cholesterol (HDLC) were analyzed by colorimetry, and ELISA was used to measure the contents of serum interleukin-1β (IL-1β) and interleukin-6 (IL-6). Results The ApoE－/－ mice model of C.pn infection was established successfully. Compared with the control group, lipid deposition in aorta and aortic root of ApoE－/－ mice increased by 89.08% and 71.83%, and As lesion area increased by 34.12% after C.pn infection (all P＜0.05). Compared with the C.pn infection group, lipid deposition in aorta and aortic root reduced by 46.16% and 75.73%, and the lesion area of As decreased by 63.37% in the TLR2－/－＋C.pn infection group (all P＜0.05). Compared with the TLR2－/－＋C.pn infection group, lipid deposition in aorta and aortic root decreased by 26.19% and 56.94%, and the lesion area of As decreased by 22.24 % in the TLR2－/－＋AMD3100＋C.pn infection group (all P＜0.05). Compared with the control group, serum levels of TC, TG and LDLC increased by 0.62 times, 1.43 times and 1.34 times after C.pn infection, respectively, while serum contents of IL-1β and IL-6 increased by 4.10 times and 6.00 times, respectively (all P＜0.05). Compared with the C.pn infection group, serum levels of TC, TG and LDLC in the TLR2－/－＋C.pn infection group decreased by 56.96%, 50.41% and 66.64%, and serum contents of IL-1β and IL-6 also decreased by 66.72% and 69.54% respectively (all P＜0.05). Compared with the TLR2－/－＋C.pn infection group, serum levels of TC, TG and LDLC in the TLR2－/－＋AMD3100＋C.pn infection group decreased by 52.18%, 58.56% and 60.61%, and serum contents of IL-1β and IL-6 and reduced by 28.84% and 43.18%, respectively (all P＜0.05). Conclusion CXCR4 enhances the roles of TLR2 in increasing the serum lipid levels and the contents of inflammatory factors, and then participates in the formation of As lesions induced by C.pn infection.