The directionally solidified specimens of Nb-13.52 Si-22.60 Ti-6.88 Hf-2.54 Cr-2.24 Al alloy were prepared in an electron beam floating zone melting furnace at the withdrawing rate of 0.1, 0.3, 0.6, 1.0, 2.4 and 6.0 mm/min. All the primary Nb solid solution (Nb-SS) columns, Nb-SS + (Nb)(3)Si/(Nb)(5)Si-3 eutectic colonies and divorced (Nb)(3)Si/(Nb)(5)Si-3 plates or chains align well along the longitudinal axis of the specimens. With increasing of the withdrawing rate, the microstructure is gradually refined, and the amount of Nb-SS + (Nb)(3)Si/(Nb)(5)Si-3 eutectic colonies increases. Both the room temperature ultimate tensile strength sigma(b) and fracture toughness K-Q are improved for the directionally solidified specimens. The tensile fracture occurs in a cleavage way.