This research was conducted to describe science process skills of ten grader high school students in Kisaran City, and to find out their score in each aspect of science process skills. This research was descriptive quantitative which describe and explain data based on real situation occurred on field. Research population was all ten grader high school students in Kisaran City, which was taken by purposive sampling. Student's science process skills were measured by using 9 questions of essay test about environmental pollution. The result showed that the average score of student's science process skills were 78, 49 (good category). The lowest aspect was found at aspect of hypothesis with average score 56.46 (poor category).