Abstract: Objective To analyze accuracy rate of intraoperative frozen section in diagnosis of papillary thyroid microcarcinoma and its influencing factors. Methods A total of 30 patients with papillary thyroid microcarcinoma were selected and treated with operation. The pathological examination of frozen section was performed during the operation, and the routine paraffin section was performed after the operation. The results of paraffin section were considered as the gold standard for disease diagnosis. The consistency between the results of intraoperative frozen section and gold standard was analyzed, and the relevant factors affecting the accuracy rate of pathological diagnosis of frozen section were explored. Results All the 30 patients were diagnosed as papillary thyroid microcarcinoma by paraffin section, and the diagnosis rate was 100.00%. The pathological diagnosis of frozen section showed that 23 patients were diagnosed as papillary thyroid microcarcinoma, with a diagnosis rate of 76.67%; 3 patients were missed because the frozen section was not cut with the pathological tissue, with a diagnosis rate of 10.00%; 3 patients were delayed in diagnosis, with a diagnosis rate of 10.00%; 1 patient was misdiagnosed as Hashimoto's thyroiditis and follicular adenoma, with a misdiagnosis rate of 3.33%. The single factors affecting the accuracy rate of pathological diagnosis of frozen section included tumor diameter, classification of thyroid calcification and condition of capsule invasion(P<0.05 or P<0.01). The results of multivariate regression analysis showed that capsule invasion(invasive growth)and tumor diameter were independent risk factors affecting the accuracy rate of pathological diagnosis of frozen section(P<0.01). Conclusion The method of intraoperative pathological frozen section has a high accuracy rate in the diagnosis of papillary thyroid microcarcinoma, - but it is also affected by many factors, so relevant measures should be taken to avoid secondary surgical trauma to patients.