  Moduli space dynamics of multi-D-vortices from D2${\bar {\rm D}}$
(equivalently, parallel straight D-strings from D3${\bar {\rm D}}$3) is
systematically studied. For the BPS D-vortices, we show through exact
calculations that the classical motion of randomly-distributed $n$ D-vortices
is governed by a relativistic Lagrangian of free massive point-particles. When
the head-on collision of two identical BPS D-vortices of zero radius is
considered, it predicts either 90${}^{\circ}$ scattering or 0${}^{\circ}$
scattering equivalent to 180${}^{\circ}$ scattering. Since the former leads to
a reconnection of two identical D-strings and the latter does to a case of
their passing through each other, two possibilities are consistent with the
prediction of string theory. It is also shown that the force between two
non-BPS vortices is repulsive. Although the obtained moduli space dynamics of
multi-BPS-D-vortices is exact in classical regime, the quantum effect of an
F-string pair production should be included in determining the probabilities of
the reconnection and the passing through for fast-moving cosmic superstrings.
