However, the differential equations encountered in production practice and scientific and technological research are often very complex. In most cases, the analytical expression of the solution cannot be obtained. Even if the formal solution can be obtained, it is often not due to the large amount of calculation It is too practical, and it is not easy to find roots of higher-order algebraic equations, so it is not appropriate to calculate numerical solutions of differential equations by seeking analytical solutions. In fact, for the problem of solving the initial value of differential equations, only the approximate solution of the obtained solution at several points or the expression of the solution that is easy to calculate is generally required.