at first i try to paint it entirely on olive drab color.but I realized that after staying in combat for weeks and months,the olive color began to wane.do the olve drab begining to look like olive green?

Are you talking about the overall green jungle fatigues? If so, yes, they faded quickly. I use medium green for used and faded jungle fatigues. You can also dry brush them with some OD green and green-grey to simulate the fading well.