As Flash - a relatively new rich media format becomes more and more popular on the Web, genre becomes increasingly important for Flash movie management as a complement to topical principles of classification. Genre classification can identify Flash movies authored in a style to most likely satisfy a user's information need. In this paper we present a method for detecting the Flash genre quickly and easily by employing a Bayesian approach. A feature set for representing genre information was proposed and used to build automatic genre classification algorithms. The performance of the proposed approach was evaluated by training a Bayesian classifier on real-world data sets. Classification results from our experiments on thousands of Flash movies demonstrate the usefulness of this approach.