This paper is organized as follows. In Section II, we present the self-consistent thermodynamics of the magnetized quark matter in the quasiparticle model. The medium effect is included by introducing the effective bag function. The surface tension is modified by an additional term dependent on the bag function. In Section III, the numerical results for the confinement bag function and surface tension are shown in the strong magnetic field. The detailed discussions are focused on the anisotropy of the surface tension. The last section is a short summary.