BRAF V600E mutation is proved critical in the progression and invasion of thyroid cancer, and as a prognostic biomarker. As anaplastic thyroid cancer (ATC) is a rare and aggressive form of thyroid cancer, this study was conducted to provide a view on prevalence of BRAF V600E as well as the best molecular diagnostic method in ATC patients. A comprehensive literature search was performed from their inception to Oct 2022 in PubMed, Scopus, Google Scholar, and Web of Science (WoS). The data of the prevalence of ATC were extracted. Moreover, the diagnostic feature of the available diagnostic tools was extracted to measure the sensitivity and specificity. To pool the prevalence data, we used meta-proportion analysis and diagnostic meta-analysis was conducted to determine the specificity and sensitivity of the immunohistochemistry method in detecting BRAF V600E mutation among patients with ATC. Overall, 34 studies were included in this meta-analysis. The incidence of BRAF V600E was shown 33% in the 978 patients. The sensitivity and specificity of IHC in detecting BRAF V600E were detected 78.9% (95%CI: 60.1-97.2), and 69.7% (95%CI: 41.2-98.1), respectively. IHC had an acceptable prognostic profile for detecting BRAF V600E in ATC patients. The diagnosis of BRAF mutation is critical in clinical trials and may be helpful for choosing proper-targeted therapy strategies in ATC patients.