The samples cut from the arc-melted Nb-14Si-22Ti-2Hf-2Al-4Cr alloy were directionally solidified in an optical imaging floating zone furnace under argon atmosphere with different growth rates. The effects of directional solidification (DS) technique on phase composition, microstructure characteristics and the mechanical properties at room and high temperatures were investigated with those of arc-melted alloys for comparison. Results show that compared with the arc-melted alloys, the DS samples are still composed of NbSS (Nb solid solution) and Nb5Si3, without any change. Nbss of DS alloys is dendritic, and the lath-like Nb5Si3 distributes along growth direction. The compressive strength of the samples at the DS speeds of 15 and 10 mm/h increase to 442 and 493 MPa at 1250 oC respectively, from 290 MPa of arc-melted alloys. After DS at 15 mm/h, the fracture toughness of the samples increases to 15 MPa·m1/2 from 12 MPa·m1/2 of the arc-melted alloys. The alloys prepared by the optical floating DS method possess good mechanical properties at room and high temperature