But why is the natural evolution prefer green colour and not the other colors like blue, purple or orange?. Why ? I mean that is there are any different between the molecule that reflect a specific color like the green wave only reflect green wave and blue waves reflect only the blue waves. What about a blue plant? It must be cool right?

As far as I understand it, the reason for plants being green is mainly because of the energy cost efficency. There's a study by Marosvölgyi et al., which explains the details.