One can easily understand the transition from special relativity to Newton mechanics under the condition of v/c 1. But it is not so easy to understand the transition from quantum representation to classical representation from the point of view of wave mechanics. We define such a quantum state as near classical state (NCS), in which the mean value of coordinates equals the classical solution on a macroscopic scale. We take the NCS for three-dimensional isotropic harmonic oscillator in a spherical coordinate system for example. We take and choose cnl =(1/(2N+1))(1/(2lM+1)). The mean values of coordinates are r2 =(Ecl)/(2)(1+1-((2Lcl2)/(Ecl2)cos(2t)) and tg = (Ecl/lcl)[1-1-((Lcl)/(Ecl)2]tg(t)) in this NCS, which are in agreement with the classical solution on a macroscopic scale, where N/N1, lM/lM1. N and lM are determined by the macroscopic state. N =[(Ecl)/(ħ)], Ecl = 1/22(a2+ b2) , lM= [Lcl}/ħ], and Lcl = ab. Here , Ecl and Lcl respectively denote the mass, the energy and the angular momentum of harmonic oscillator. And the bracket [c] means taking the integer part of the number c, for example [2.78]=2. It is also emphasized that for a definite macro state, there are many NCS corresponding to a macro state; just like the case in statistical physics, many micro dynamical states correspond to a macro thermodynamic state. Thus the transition from quantum representation to classical representation is a coarse-graining process and also an information losing process.