  We first bring up the concept of spin-current Seebeck effect based on a
recent experiment [Nat. Phys. {\bf 8}, 313 (2012)], and investigate the
spin-current Seebeck effect in quantum dot (QD) systems. Our results show that
the spin-current Seebeck coefficient $S$ is sensitive to different polarization
states of QD, and therefore can be used to detect the polarization state of QD
and monitor the transitions between different polarization states of QD. The
intradot Coulomb interaction can greatly enhance the $S$ due to the stronger
polarization of QD. By using the parameters for a typical QD, we demonstrate
that the maximum $S$ can be enhanced by a factor of 80. On the other hand, for
a QD whose Coulomb interaction is negligible, we show that one can still obtain
a large $S$ by applying an external magnetic field.
