Based on an analysis of Chubosokhae 推步續解 (A Follow-up Commentary on the Astronomical Calculation, 1862) and other documents written by Nam Pyŏng-ch'ŏl 南秉哲 (1817-1863), in this paper, I examine the following aspects of his work: (1) the achievement of his astronomy and natural studies, (2) his attitude to western science and his evaluation of it, (3) the influence of evidential studies of the Qianjia 乾嘉 period (1736-1820) of Qing China and its relationship with Nam’s natural studies, and (4) the object and meaning of natural studies from his Confucian perspective. Nam’s study of astronomy, most of all, showed the highest level of consistency and systematization on the technical side. He had full confidence in western science because western astronomy was equipped with good accuracy and efficiency in calculating the movement of celestial bodies and making an annual calendar with it. Nam’s amity with western astronomy was deeply related to that of Chiang Yung’s 江永 (1681-1762), a Chinese scholar of evidential study. Nam also learned the evidential methodology from scholars of evidential studies of the Qianjia period and he always examined astronomical proofs when he discussed astronomical theories. No matter how his natural study assumed evidential character, however, it was never an independent field of modern science. Natural study to him was a secondary field of Confucian study, which was always a pursuit of being an ethical sage. Western science, therefore, had only a technical value, while Confucian study possessed the excellence of ethical and cultural value.