  Let $ L $ be an $ n $-dimensional non-abelian nilpotent Lie algebra and $
s(L)=\frac{1}{2}(n-1)(n-2)+1-\dim \mathcal{M}(L) $ where $ \mathcal{M}(L) $ is
the Schur multiplier of a Lie algebra $ L. $ The structures of nilpotent Lie
algebras $ L $ when $ s(L)\in \lbrace 0,1,2,3,4,5\rbrace $ are determined. In
this paper, we classify all non-abelian nilpotent Lie algebras $ L $ when $
s(L)=6,7. $
