The purpose of this study was to examine the effects of the Korean phonological rules instruction program combining reading and spelling on multicultural children s Korean reading and spelling accuracy. Because Korean pronunciation doesn t match with spelling, multicultural children have difficulty in reading and spelling the Korean words that changes according to phonological rules. As a systematical approach, the intervention consisted of 12 stages of 8 phonological rules. The intervention participants were four elementary multicultural children. Single subject research design based on delayed multiple baseline across participants was conducted for the study. The results of the study can be summarized as follows. First, the four elementary children participants showed high level of phonological rule acquisition and progression at each stage along with improved accuracy of reading and spelling Korean words that change according to the phonological rules. Second, applying Korean phonological rules were generalized to other words that were not included in the intervention program, and the ability to generalize the learned phonological rules revealed to be maintained even twenty-seven days after the termination of the intervention. The results of this study indicated that the phonological rules instruction program combining reading and spelling was effective in improving the accuracy of reading and spelling Korean words with phonological change. These findings provide useful evidence for teaching multicultural children who have problems with reading and spelling Korean words with phonological change. Based on the study results, some limitations of the current study and implications for the further study are discussed.