Does anyone know how to overlay a equalized CDF plot with equalized histogram in matlab?
You can use 'hold on' with a histogram:

[n,x]=hist(rand(1,100),20);  % find the histogram
bar(x,n./sum(n))             % plot normalized histogram
hold on                      % don't delete current plot
plot([0 1],[0.1 0.1])        % plot a uniform pdf
axis([0 1 0 0.12])           % make room around the plot


Another example using a normal distribution, which shows how to normalize the histogram so that its area is one:

r=randn(1,1000);      % normal random variable
[n,x]=hist(r,25);
delta=x(2)-x(1);
n=n./(delta*sum(n));  % n is normalized so that its area is 1
bar(x,n)
hold on
d=-4:0.1:4;
plot(d,(1/sqrt(2*pi))*exp(-(d.*d)./2),'r')  % plot of the normal pdf