This study is to find an effect of Simultaneous -Successive Process Training of PREP on reading skill in children with reading disabilities. Research subjects were two students with reading disabilities from D elemental school in Daegu, and experiment was conducted 3 times a week for 6 weeks and each session ranged from 20 to 40 minutes. The researcher used a Simultaneous- Successive Process Training of PREP Program which had been reconstructed from a program made by Jung-Mi Choi. The assessment method was also reconstructed from Jung-Mi Choi’s meaning and non-meaning words reading assessment and sentence comprehension assessment. As for data-processing method, reading skill of children with reading disabilities was calculated as scores to process the Representation Multiple baseline across subjects graph. The conclusions obtained from this research are as follows: * Daegu Dalseong Elementary School ** Daegu National University of Education First, simultaneous-successive process training of PREP is effective on reading skill related to meaning words in children with reading disabilities. Improved meaning words reading skill seems to be achieved from reading syllables that became visually familiar by going through repeated activities. Second, simultaneous-successive process training of PREP is effective on reading skill related to non-meaning words in children with reading disabilities. They took part in activities with confidence and were able to read each word with no meaning. This led to an improvement in their non-meaning words reading skill. Third, simultaneous-successive process training of PREP is effective on sentence comprehension skill in children with reading disabilities. To naturally find pictures that matched sentences made of over three words seemed to lead to an improvement in sentence comprehension skill. Key wards : Simultaneous-Successive Process Training of PREP, children with reading disabilities, reading skill.