There is an accumulating body of evidence indicating association between inflammation and the pathogenesis of coronary vasospastic angina (CVA). Interleukin-6 (IL-6) is a pleiotropic cytokine, functions as a mediator of inflammatory response and has both pro-inflammatory and anti-inflammatory properties. The aim of the present study is to investigate the association of -634C/G polymorphism of IL-6 gene with CVA in Han Chinese. A total of 27 CVA patients and 232 healthy controls were eligible for this study. The PCR-based restriction fragment length polymorphism (PCR-RFLP) technique was used to assess the genotypes frequencies. The distribution of the IL-6 -634C/G genotypes (CC, CG, and GG) was 59.48%, 37.07%, and 3.45% in the controls, and 37.04%, 48.15%, and 14.81% in CVA group, respectively (P = 0.0080). The frequency of the G allele in the CVA group was significantly higher than that in the control group (38.89% vs 21.98%, P = 0.0057). Compared with the wild type CC, the G allele carriers (CG + GG genotypes) had increased risk of CVA in both unadjusted and adjusted analyses. These findings suggest that IL-6 -634C/G polymorphism is associated with CVA and the G allele is an independent risk for CVA in Han Chinese.