Abstract: Objective To explore the association of serum matrix metalloproteinase-13 (MMP-13) levels and the gene promoter -77A/G functional polymorphism with asymptomatic carotid stenosis(ACS). Methods A total of 621 ACS patients in Taizhou Hospital from June 2015 to December 2017 were divided into stenosis group (n=117,stenosis≥50%) and the control group (n=504, stenosis<50%) according to carotid ultrasound examination. Serum MMP-13 levels were measured by enzyme linked immunosorbent assay, and MMP13-77A/G genotypes were determined by polymerase chain reaction-restriction fragment length polymorphim. Results The difference of serum MMP-13 levels between stenosis group and the control group were significant(P<0.01). The A allele frequency (MMP13-77A/G polymorphism) was higher in the stenosis group [OR=1.861; 95%CI(1.398-2.478)]. After adjustment for vascular risk factors binary logistic regression analysis showed that both AG and AA genotypes in stenosis group were significantly higher than those in the control group [AG:OR=1.833, 95% CI(1.108-3.033); AA:OR=3.197, 95%CI:1.777-5.792)]. Conclusion The serum level of MMP-13 and the gene-77A/G polymorphism are closely related to the risk of ACS with carotid stenosis≥50%, -77A allele may be a genetic predisposing factor for ACS.