Background: Diabetes mellitus is a major factor in clopidogrel resistance (CR), and the glucokinase (GCK) gene plays a pivotal role in glucose homeostasis. This study investigated the contribution of GCK polymorphisms to CR risk. Methods: Two hundred SCAD patients were recruited, and their platelet functions were detected by the Verify-Now P2Y12 assay. The polymorphisms of GCK were tested based on the methods of polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP). We investigated the associations of GCK polymorphisms and CR. Multivariate logistic regression was performed to analyse the correlations between GCK polymorphisms and clinical values. Results: Our study found that the SNPs rs4607517 and rs6975024 were associated with CR. Additionally, patients with the G allele of rs4607517had a greater CR risk, but the C allele of rs6975024 might be a protective factor. Finally, logistic regression revealed that CC + TC (rs6975024) as well as the values of albumin were correlated with a decreased risk of CR, and higher levels of uric acid (UA) may be positively associated with CR. Conclusion: The GCK gene polymorphisms might increase the CR risk in SCAD patients. Meanwhile, higher albumin levels and lower UA values might decrease the risk.