Ni-(50-x)Al-xSc (at%) alloys were prepared by using vacuum arc smelting furnace with a water-cooled copper mold. The microstructures of the alloys were observed by optical microscope and scanning electron microscope (SEM). The phases of the alloys were analyzed by X-ray diffraction (XRD) and energy spectrum (EDS). The solidification processes of the alloys were analyzed based on scanning calorimetry (DSC) analyzing results. The mechanical properties of the alloys were analyzed by micro Vickers hardness test and nanoindentation test. With the two-phase system simplified model, the overall elastic moduli of the alloys were estimated. The results show that the sub-rapid solidification structures of Ni-50Al, Ni-45Al-5Sc, Ni-40Al-10Sc and Ni-35Al-15Sc alloys are NiAl, NiAl+AlNi₂Sc, NiAl+AlNi₂Sc and NiAl+AlNi₂Sc+(AlNi₂Sc+Ni-16.93Al-21.53Sc), respectively. The precipitation ordered of each phase in the alloys are in the ordered of NiAl, AlNi₂Sc and (AlNi₂Sc+Ni-16.93Al-21.53Sc) accordingly. The value of crystal growth Jackson factor of AlNi₂Sc compound was α = 0.2, which is much smaller than 2, which means AlNi₂Sc phase growths in a continuous manner and a coarse solid/liquid interface. The hardness of the primary NiAl phase is increased by alloying with Sc element and the hardness of the secondary phase AlNi₂Sc is greater than the primary NiAl phase. Therefore, the hardnesses of the Ni-(50-x)Al-xSc alloys increased. Alloying with Sc can reduce the elastic modulus of the primary NiAl phase, and the overall elastic moduli of Ni-(50-x)Al-xSc alloys decrease compared with that of the NiAl intermetallic compound.