The effect of water toughening treatment on mechanical properties of high manganese steel bonded TiC hard alloy was systemically investigated, and the microstructure and element distribution of the alloy before and after the treatment were also evaluated by SEM and EDS in order to understand the internal relationship with its properties. The bending strength and impact toughness of high manganese steel bonded TiC hard alloy by normal vacuum sintering were increased by 154.6% and 125.3%, but those of low pressure sintering specimens were increased by 61.81% and 45.38%, and 65.59% and 32.90% for vacuum and low pressure sintering specimens, respectively. The results revealed that water toughening treatment could effectively improve the bending strength and impact toughness of the steel bond hard alloy. As-sintered steel-bonded TiC hard alloy should be heating treated by water toughening treatment or high temperature homogenizing treatment for better mechanical properties.