Objective To explore the risk factors of postoperative head and neck surgical site infection in patients with type Ⅱ incision head and neck cancer. Methods Retrospective analysis of the clinical data of patients with head and neck cancer who underwent surgical treatment in the department of ENT in our hospital from January 2018 to December 2019.Risk factors for surgical site infection were analyzed using chi-square test, Mann-Whitney U test, and multivariate logistic regression analysis, and Machine learning methods are used to rank the weights of risk factors.Results A total of 432 patients with head and neck cancer surgery met the inclusion criteria, and 73 patients developed surgical site infections after surgery, with an infection rate of about 15.77%. Diabetes mellitus, primary tumor site (base of the mouth), flap failure, preoperative radiotherapy, and bilateral cervical lymph node dissection are risk factors for postoperative infection of head and neck cancer. After weight analysis of the possible risk factors for surgical site infection using machine learning, it was found that diabetes, primary tumor site (bottom of the mouth), and flap failure are the top three risk factors that may cause infection at the surgical site. In addition, surgical site infection can significantly increase the risk of hospital stays and flap failure.Conclusion Diabetes mellitus, tumor site (base of the mouth), flap failure, preoperative radiotherapy, and bilateral cervical lymph node dissection are risk factors for postoperative infection of head and neck cancer.