  The magnetic field and density behaviors of various thermodynamic quantities
of strange quark matter under compact star conditions are investigated in the
framework of the thermodynamically self-consistent quasiparticle model. For
individual species, a larger number density $n_i$ leads to a larger magnetic
field strength threshold that align all particles parallel or antiparallel to
the magnetic field. Accordingly, in contrast to the finite baryon density
effect which reduces the spin polarization of magnetized strange quark matter,
the magnetic field effect leads to an enhancement of it. We also compute the
sound velocity as a function of the baryon density and find the sound velocity
shows an obvious oscillation with increasing density. Except for the
oscillation, similar to the zero-magnetic field case that the sound velocity
grows with increasing density and approaches the conformal limit $V_s^2=1/3$ at
high densities from below.
