Research on fairy tales in general and miracle fairy tales in particular in terms of type and motif has been effectively applied by Folklore researchers in the world. In Vietnam, in recent years, this research trend has been becoming popular and achieves high practical values. By comparison the miracle fairy tales of Vietnamese people and Khmer people, this method is important in finding similarities and differences in miracle fairy tales systems of people in the same territory in term of literature and culture. In this article, by statistics, analysis and synthesis, some typical miracle fairy tales with the theme of “Hero kills Monster” type of Vietnamese people and Khmer people were chosen for comparison to figure out the similarities.