Now, I can give a solution.
for matrix A=[1 2; 2 3; 1 2], the following function can be used to find the same row in the matrix A.

function result=find_same_row(A)

[rowA,colA]=size(A);
B=unique(A,'rows');
[rowB,colB]=size(B);
for i=1:rowB
temp=B(i,:);
result=find((min((A==temp(ones(1,rowA),:)),[],2))');
end

For example, A=[1 2 ;2 3; 1 2; 1 2].
How can i find the rows which have the same elelments in A? Is it clear this time?