The motion system of a toy robotic snake is discussed. This study is expected to provide the best design for this toy and to help widen future application. A mathematical model was constructed after a literature and mechanical design survey. Tribotix AI 1001 motors are used to operate the snake. By an analysis of the mathematical model, transformation of the D-H matrices, and the introduction of forward and inverse kinematics, the relationship between the angle and the coordinate of each section of the robotic snake were determined. The trace curve of a real snake was also studied to arrive at a description of the motion and parameter changes for the robotic snake within a single time unit. MATLAB was used for the simulation and to plot the figures. Experiments and trace analyses were also performed to obtain the design rule and an approach to an improved mechanism for the toy robotic snake. Finally, the experimental results and the possibility of future development are discussed.