A DC/DC converter is a typical kind of hybrid system. It is difficult to characterize its hybrid characteristics by traditional modeling methods. In this paper, a v-step modeling approach is introduced to deeply analyze the dynamic process of parallel DC/DC converter and deduce its dynamic evolution equation, thus yielding the mixed logical dynamical (MLD) model. On the basis of it, a control strategy combining model predictive control and interleaving PWM technology is proposed to implement the optimal control of a DC/DC converter. In order to verify the effectiveness of the control, a system simulation experiment is made. And the obtained results show that the strategy enables the system to quickly and efficiently track the reference signal and quickly return to its steady state with small magnitude change even in such a case where the input voltage or load resistance suddenly changes, the system has a good dynamic performance.