We conducted a comprehensive analysis to evaluate the benefits of negative pressure wound therapy (NPWT) versus traditional dressings in preventing surgical site infections in patients undergoing cardiac surgery. We thoroughly examined several databases, including PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure (CNKI), VIP, Chinese Biomedical Literature Database (CBM) and Wanfang, from inception until July 2023. Two independent researchers were responsible for the literature screening, data extraction and quality assessment; analyses were performed using RevMan 5.4 software. Thirteen studies comprising 8495 patients were deemed relevant. A total of 2685 patients were treated with NPWT, whereas 5810 received conventional dressings. The findings revealed that NPWT was more effective in reducing surgical site infections after cardiac surgery than conventional dressings (4.88% vs. 5.87%, odds ratio [OR]: 0.50, 95% confidence intervals [CIs]: 0.40-0.63, p < 0.001). Additionally, NPWT was more effective in reducing deep wound infections (1.48% vs. 4.15%, OR: 0.36, 95% CI: 0.23-0.56, p < 0.001) and resulted in shorter hospital stays (SMD: -0.33, 95% CIs: -0.54 to -0.13, p = 0.001). However, the rate of superficial wound infections was not significantly affected by the method of wound care (3.72% vs. 5.51%, OR: 0.63, 95% CI: 0.32-1.23, p = 0.180). In conclusion, NPWT was shown to be advantageous in preventing postoperative infections and reducing hospital stay durations in patients undergoing cardiac surgery. Nonetheless, given the limitations in the number and quality of the included studies, further research is recommended to validate these findings.