Abstract: The aims of this study were to explore the associations among the eye movement behaviors, task difficulties and task performance during the abductive reasoning tasks in different difficulties involving genetics. Fifty-five college students were recruited to participate in this study. They were asked to determine the following two main questions: whether the genetic disease is color blindness and whether the X-linked disease is dominance or recessiveness according to the pedigree charts in 15s (task difficulty: task 2>task 1). Each main question was followed by 50 pedigree questions. The results showed the mean accuracy in task 1 was significantly higher than in task 2 (T(54) = 7.470, p = .008). The fixation number (F(1,5187)=11.77, p=.001), total fixation duration (F(1,5187) =11.78, p=.001) and re-reading number (F(1,5187)=3.90, p=.048) within the areas of interest (AOI) for the correct responses were significantly greater than those for the incorrect responses across task 1 and task 2. The mean re-reading time within the AOI for task 2 was greater than that for task 1 across the correct and incorrect responses (F(1,5187)=6.13, p=.013). To summary, this study demonstrated that subjects allocated greater attention on AOI for the high difficulty task than the low one and for the correct responses than the incorrect ones. It could help to uncover the cognitive processes involved in the on-line abductive reasoning.