In this paper the mathematic model and kinematics of robotic arm are mainly analyzed. The robotic arm uses the Denavit Hartenberg (D-H) method to determine the parameters with transformation matrices. The direct kinematic analysis was conducted to determine the parameter of robotic arm by using Denavit Hartenberg (D-H) method. The calculated parameters of robotic arm were implemented by direct kinematics and compared with the measured parameter by rotary encoder to determine the accuracy of each parameter.