  In this paper, we give a recursive formula for the interesting PBW basis
$E_{A}$ of composition subalgebras of Ringel-Hall algebras $\fkH_\vartri(n)$ of
cyclic quivers after \cite{DengDuXiao2007generic}, and another construction of
canonical bases of $\U_v^+(\wih{\fks\fkl}_n)$ from the monomial bases $m^{(A)}$
follow \cite{DuZhaomultiplication}. As an application, we will determined all
the canonical basis of $\U_v^+(\wih{\fks\fkl}_2)$ associated with modules of
Lowery length $\leqs3$. Finally, we will discuss the relation of canonical
bases of Ringel-Hall algebras and those of affine quantum Schur algebras.
