The purpose of this study was to analyze abductive reasoning on the inquiry of scientists and elementary school gifted children in science. Subjects for this study were eight scientists and eight elementary school gifted children in science studying in the Academy of Gifted Child Education in Science affiliated with Seoul National University of Education. As a result, abductive reasoning on the scientific inquiry of scientists and gifted children showed the three stages of generating hypotheses, designing the experiments, and interpreting the results. The abductive reasoning in each stage characterized the five types as complex abduction, analogical abduction, observation-based abduction, logic-based abduction, selective abduction. The sub-reasoning process of the abductive reasoning of gifted children in science differed in some ways from that of scientists. First, for most scientists, representing a method or representing a casual explican appeared after searching for the characteristics of variables but for gifted children in science, searching for the characteristics of variables appeared after representing a method. Second, scientists tend to rely on logic-based abduction but gifted children in science tend to rely on observationbased abduction. Third, scientists reason by the similar rate in three steps: generating the hypothesis, designing the experience, interpreting the results. On the other hand, most gifted children in science reason about designing the experience.