This paper studies a second order linear ordinary differential equation with n-turning points Where q1=(x-µ1)(x-µ2)…(x-µn)ƒ(x)≠0,and λ is a large parameter.The formal uniformly valid asymptotic solution of the equation is obtained based on the analysis of the three points by means of the matched method.By the work a method is developed and the applicability of this method to the n-turning points is demonstrated.