The design and the implementation of the teen-sized humanoid robot named David Junior is presented in this paper. David Junior has 26 Degree of Freedom, and aluminum-magnesium has been widely applied for this teen-sized robot. The special designs of the thumb structure, the flexible leg, and the enhanced hip are also introduced in this paper. In order to ensure the strength of each mechanism and the deformation is in a safe range, the stress analysis is also adopted in this work. The best ratio of weight and strength can be achieved by the stress analysis. Finally, the competition results in HuroCup 2015 also demonstrate the performance and feasibility of the designed teen-sized humanoid robot.