Titanium-Boron-Aluminium master alloys are used extensively to grain-refine a wide range of aluminium alloys. This experiment was performed by various amount of AlTi5B1 addition to the technical aluminium alloys, and also by changing cast temperature and hold time of the melts. The macrostructures were shown that with increasing the addition of AlTi5B1 to the melts, the grain became finer. In the case of cast temperature high enough over 900℃, the grain became coarser, but hold time change not affected on the grain refinement. Particles of TiAl₃and TiB₂were found in the grains and grainboundaries. The Important role of grain refinement in this experiment were mainly TiAl₃and also TiB₂those have been confirmed in TEM, SEM, EDS, WDX and X-ray diffraction.