If the matrices are small, you can subtract them:
A - B
abs(A- B)
If they are too large to keep the overview in the command window:
D = abs(A - B);
max(D(:))
min(D(:));
You can draw the difference:
Img = A - B;
Img = Img - min(Img(:));
Img = Img / max(Img(:)); % Normalize to [0, 1]
image(Img);
If you only want to check, if the matrices are equal:
isequal(A, B)
