This research is Classroom Action Research, which includes planning, action, observation, and reflection. Actions are made to obtain an overview of the application of guided discovery methods in improving the skills of the physical science process conducted in two cycles. This research was implemented in SMA Negeri 1 Kolaka class XI IPA 1 in the second semester of academic year 2015/2016. The results showed that in the first cycle the average score is 30.9; the second cycle got an average score is 91.8. The increase of the score in each cycle is 78.18%. It means that there is an improvement in the Physics Science Process skills of Learners. Furthermore, the observation of teacher and learners activity shows the implementation. This research concludes that the applicated of guided discovery method can improve the Physics Science Process skill in second-grade students of IPA 1 at SMA Negeri 1 Kolaka by observation, formulating problems, proposing hypotheses, planning problem solving, conducting experiments, observing and collecting data, data analysis, drawing a conclusion.