  The thermodynamics of finite size quark matter in the quasiparticle model is
self-consistently constructed by an effective bag function, which presents the
medium effect to the confinement. We obtained completely analytic surface
tension in the strong magnetic field with the multiple reflection expansion.
The anisotropic structure is demonstrated by the splitting of the longitudinal
and transverse surface tensions. The anisotropy of the surface tension could be
enhanced by an increase of the magnetic field. The analytical surface tension
is modified by an additional term related to the bag function. For strong
enough magnetic fields, the increase of the longitudinal surface tension is
proportional to the magnetic field.On the contrary, the transverse component
vanishes due to all quarks locating in the lowest landau level.
