  Quantum superalgebras $su_{q}(m\mid n)$ are studied in the framework of
$R$-matrix formalism. Explicit parametrization of $L^{(+)}$ and $L^{(-)}$
matrices in terms of $su_{q}(m\mid n)$ generators are presented. We also show
that quantum deformation of nonsimple superalgebra $su(n\mid n)$ requires its
extension to $u(n\mid n)$.
