In this paper, the understanding of an algorithm for numerical computation via Newton's method is investigated. In order to demonstrate the efficiency of Newton's method, an example of how to use them is given. After introducing the mathematical tool related to matrix algebra, the new iterative technique that is based on Newton's method for solving a set of the algebraic Riccati equation is applied. It is shown that the proposed algorithm guarantees the local quadratic convergence. A numerical example to show the validity of the Newton's method is given for the practical control problem.