Hi friends…
I wanna change the material of my game object… after changing, the color of previous material still is on my game object…
for example: if previous material color be red and the next game object be green, my next game object take red as its color
You have to use new materials for the different colored objects you want. 
well the problem is fixed by now…
I had an animation on my gameObject and it was preventing the color to change