It is proposed to improve the dynamic model of pantograph in which the degree of freedom is increased and the effects caused by contact wire deviation, a pantograph-head interval and the pitching mode of a pan-head support can be examined. In addition, a technique to improve the compliance characteristics of pantograph such as shifting the natural frequency of a pantograph-head has been proposed, and the model calculation and experiments have confirmed the validity of our proposal. Furthermore, technique for selecting optimum value of spring constant using Genetic Algorithm has been proposed.