[max_value max_idx] = max(A);
The position is in the second argument, max_idx
doc max
Edit : Also, regarding your previous question : http://www.mathworks.com/matlabcentral/answers/154462-how-to-find-the-maximum-value-of-an-image-by-using-buit-in-function-in-matlab
You should try learning the basics of Matlab with this link , it will be easier than to ask every time you get stuck by something which is written in the documentation .
