A new method is proposed to prepare bulk nanocrystalline alloys by quenching alloy melts under high pressure. Due to application of pressure to solidification processes, the nucleation rate is increased whereas the growth rate of nuclei decreased with increase of pressure, which makes it possible to obtain bulk ingots with nanometer-sized crystalline grains if appropriate pressure, temperature, and cooling rate are selected. The as-pressure-quenched products are cylinder-like with diameter about 4 mm and height several millimeters. This method can produce dense, free-porosity bulk nanocrystalline alloys with clean crystalline interfaces, promising use for experimental research and technological applications.