The invention relates to a method for detecting release condition of tobacco specific nitrosamines (TSNAs) in a buccal tobacco product. The method is characterized in that: the release condition of the TSNAs in the buccal tobacco product in a human oral cavity is simulated, and release quantity and release speed are quantified timely, so that the in-vitro release speed and release degree of the TSNAs in the buccal tobacco product are detected. TSNAs release collection is realized by an in-vitro release collecting device which can simulate the release process of the TSNAs in the product in the human oral cavity and can collect TSNAs release liquid on line; and the TSNAs content of the release liquid is detected by a liquid chromatogram-electrospray tandem mass spectrum combined technique. The method has the advantages of simulating the release condition of the TSNAs in the oral tobacco product in the human oral cavity, detecting the release speed and the release degree of the TSNAs in various oral tobacco products quickly and accurately, effectively distinguishing release difference of the TSNAs in different products and contributing to popularization and application, along with high repeatability.