Objective: To investigate the diagnostic delay of patients with oral squamous cell carcinoma by self-designed questionnaire to find out the significant influencing factors, so as to identify the influencing factors of the patient’s delay and the risk of oral cancer.Methods: A total of 514 patients with primary oral squamous cell carcinoma were enrolled at Peking University School and Hospital of Stomatology from January 2014 to April 2016, including 334 men and 180 women, with a male to female ratio of 1.85 :1. The youngest participant was 21 years old, with a maximum of 89 years and a median age of 57.6 years. The position of the disease according to International Classification of Diseases-10 (ICD-10) was divided into lip, buccal, gingival, retromolar, palate, floor of the mouth, tongue, and oropharynx. The age group is divided into 10 years. The level of education was divided into illiteracy, primary education level and advanced education level. Body mass index (BMI) was divided into three levels by 18 kg/m ² and 25 kg/m ². Visual analog scale (VAS) method was to evaluate the patient’s preoperative pain. At the same time, the patients were examined by detailed questionnaire to understand the delay factors and delay characteristics, and use SPSS 18.0 software, analysis of variance and chi-square test to explore correlation.Results: Among all patients, the proportion of patients developed in the tongue was the highest (43.3%). Delay was defined by a span of three months or longer from the onset of symptoms until treatment. The delays to diagnosis according to location were as follows (in months and in descending order): lip (6.1 months), buccal (4.1 months), floor of the mouth (3.9 months), tongue (3.6 months), oropharyngeal (2.9 months), retromolar (2.7 months), palatine (2.4 months), and gingival (2.4 months). Different sites and delayed diagnosis were statistically significant (P=0.048). There were no statistically significant differences in gender, education, pain, smoking, drinking and VAS score.Conclusion: The study has found that tumor positions and delay have a significant correlation. The position of the tumor is an obvious factor associated with the findings. The lip is the most likely to delay the diagnosis of oral positions. For the lip of the lesion, more than three months’ obvious mass is recommended for timely treatment, while at admission, physicians should take the appropriate diagnostic method as soon as possible.