Abstract: A path planning algorithm based on convex hull is applied to autonomous service robot in this paper. Firstly, the coordinates of ball positions are determined by using Haar-like features classifier, the coordinate of robots position and its heading are determined by using the method based on color model. According to the features of the robot itself, the balls in a certain range can be treated as one target point. Then a better ball-picking path is elaborated with a path planning algorithm based on convex hull, which takes the target points as the input of algorithm. The algorithm alleviates the robots motion cost and improves the ball-picking efficiency of the autonomous service robot obviously.