  In this work, we briefly review the progress made in the formulation of
hydrodynamics with spin with emphasis on the application to the relativistic
heavy-ion collisions. In particular, we discuss the formulation of
hydrodynamics with spin for perfect-fluid and the first order viscous
corrections with some discussion on the calculation of spin kinetic
coefficients. Finally, we apply relativistic hydrodynamics with spin to the
relativistic heavy-ion collisions to calculate the spin polarization of
$\Lambda$-particles.
