This paper facilitates the conception of signal flow graph theory, which makes it possible to determine the angular velocity of the planetary gear trains. In design of the planetary gear train,the determination of the angular velocity of these is one of the important subjucts. In almost the method used for kinematic analysis of planetary gear train are inherent for gearing itself and are tedious. In oroder to make easy these analysis of the planetary gear train, the article proposes the representation by algebraic vector equation and graph theory for these problems. Moreover,the article presents examples of the application of this method for the complex type, 2K-H type and 3K type paradox gear trains.