  Bell nonlocality and Einstein-Podolsky-Rosen (EPR) steering are every
important quantum correlations of a composite quantum system. Bell nonlocality
of a bipartite state is a quantum correlation demonstrated by some local
quantum measurements, while EPR steering is another form of quantum
correlations, observed firstly by Schrodinger in the context of famous EPR
paradox. In this paper, we give some remarks on Bell nonlocality and EPR
steering of bipartite states, including mathematical definitions and
characterizations of these two quantum correlations, the convexity and
closedness of the set of all Bell local states and the set of all EPR
unsteerable states. We also derive a EPR-steering criteria, with which the EPR
steerability of the maximally entangled states are checked.
