It has been recently emphasized that comprehensive understanding of students` cognitive in the process of writhing as well as final product is needed in order to develop an effective strategy for science writing. In this study, we investigated the characteristics of writing process in the situation that students wrote a composition in solving the application problem on a science topic. Seven eighth graders selected in the consideration of their science achievement and communication skills were asked to write a composition using think-aloud method. They were also interviewed after their writing work. The analyses of the results indicated that students` writing processes consisted of six distinctive components: generating, organizing, translating, evaluating, and revising. It was also found that the patterns of process components for each student were different in terms the frequency and the sequence. The patterns of process components were into four types: systematic, tacit planning, trial and error, random strategies. Educational implications were also discussed.