It is reported that children with cochlear implants improve the modulation accuracy and intelligibility of articulation according to the duration of cochlear implant. The purpose of this study was to compare the phonological patterns of hearing impaired children with cochlear implant children over 5 years. The subjects who participated in the study were 11 hearing-impaired children who were wearing cochlear implants for 5 years or more and 11 hearing children, and to analyze the phonological variability of two groups phonemes, Korean phonological tests(U-TAP) were performed. All samples were analyzed by recording with a wav file. Independent sample t-tests were conducted to examine the difference in phonological variability between children with cochlear implants and hearing children. The results, there were no significant differences in phonation delinquency between cochlear implanted children and hearing children. In phonological substitution, there was no significant difference between the two groups on the articulation position. However, the children with cochlear implants showed significantly higher error rates at nasalization and nasal assimilation than those with normal children. These results suggest that nasalization errors are reduced due to normal phonological development of hearing children. Therefore, children with hearing impairment who have been wearing cochlear implants for more than 5 years can produce most of the phonemes, and the phonological variance decreases.