The incidence of thyroid carcinoma has increased at an accelerating rate in recent years.Because of the lack of typical ultraphonic images and limitation of ultrasound guided fine-needle aspiration cytology in some papillary thyroid cancers，defining preoperative diagnosis can not be acquired sometimes.As a result，researchers tend to find the key molecule about the occurrence and development of papillary thyroid cancer and try to combine this molecule with ultrasound guided fine-needle aspiration cytology to improve the accuracy rate of preoperative diagnosis and to offer a molecular evidence for papillary thyroid cancer evaluating severity.This article reviews the research progress of BRAF V600E mutation on fine-needle aspiration cytology specimens in papillary thyroid cancer diagnosis and evaluating severity.