Contents I. INTRODUCTION
Today, by using computer, network control become more and more important, there are a lot of projects about network control, and a lot of paper published about network control theory and numeric calculation. One of them is power linear ordinary differential equation problem [1], Yang [1] studied this problem in the aspects of the sufficient condition of unique solution and nun-unique solution, the property of the solutions, and the asymptotical in the starting time. Li [2] studied the positive and negative solutions distribution and their asymptotic properties in the different parameters, for a class of semi-linear timing-varying ordinary differential equations with initial value. They also pointed out the numeric calculation must be employed in the case of application. Difference method is a powerful tool to solving power linear ordinary differential equation. Zhang [3] used difference method to solve initial condition problem translated from boundary problem. His method was proved by Wei [4]. Difference method is also used to solve Schrödinger equation [5] and protein problem [6].
