Imposing an intensity variable high static magnetic field during traditional melting-solidification (MS) method has been used as a new method to prepare p-type bismuth antimony telluride thermoelectric materials in this work. On this basis, we present a systematic study of the nucleation, crystal orientation, microstructure, electrical and thermal transport properties of the obtained alloy ingots solidified under different magnetic field intensities. A c-axis alignment of bismuth antimony telluride in the direction perpendicular to the magnetic field, formation of BSTII nanorods, and a simultaneous optimization of the electrical and thermal transport properties has been observed. Consequently, an enhanced ZTmax=1.71 at 323 K has been achieved in a polycrystalline Bi0.5Sb1.5Te3 sample solidified under a 2T magnetic field.