The invention discloses an in-vitro simulation detection method for the bioavailability of nicotine in a tobacco gum base product. The in-vitro simulation detection method for the bioavailability of the nicotine in the tobacco gum base product is characterized by comprising specific steps of: (1) releasing and collecting nicotine in vitro; (2) performing quantitative analysis on the content of the nicotine in collected liquid and residual samples; and (3) drawing an in-vitro nicotine bioavailability curve. The method has the advantages that: the chewing behavior of the mouth of a person can be simulated well by using a self-designed pressure changing type simulation chewing machine; for the rationally prepared artificial saliva and the continuous updating of the artificial salvia in a chewing cavity, nicotine in the tobacco gum base product can be released fully; as nicotine release liquid can be collected in real time for detection and the test result is close to the true condition of the product used by a person, the specific data support can be provided for judging the safety of the tobacco gum base product and performing quality regulation, control and research. The method hasthe advantages of good repeatability, high sensitivity and short detection period, and is suitable for rapid analysis of samples in industries, such as tobacco, food, medicines and the like.