The acceptance of western studies(西學) of the Seongho School(星湖學派), represented by Yi, Ik(李瀷), has several characteristics as follows. Firstly, western science and technology is regarded separately from Catholicism. While he has asserted that Catholicism was a heresy, Yi, Ik has showed a positive attitude toward western science and technology. Secondly, they have affirmed the academic excellence and practicality of Western science and technology, based on historical awareness and perception of reality. They have had historical awareness that Science and technology becomes more and more precise as it goes down later, and even the wisdom of the saints can not grasp the whole truth, At the same time, they have had perception of reality that China’s academic ability was lagging behind the West at that time. Thirdly, based on the open-minded attitude of study, they have raised the selective acceptance of the doctrine of heresy. Yi Ik has the view that even if it is a book of heresy, they can remove the nuisance part and can adopt only outstanding discussion. Finally, they have explored the doctrines of Catholic and other heretic theories thoroughly. Scholars of the Seongho School have read a wide range of books related to Western learning and extracted pros and cons. This differentiates them from those scholars who have never read books of Western learning and raised criticism. Unlike the acceptance of Western learning of the Seongho School, it is difficult to find a discussion on the excellence of Western science in the Heterogeneism and the traditional logic of heretical rejection, held by those scholars belong to Southerners group and those who have strong opinion of defending orthodoxy and rejecting heterodoxy. Based on the tradition of heretical rejection, they have categorized Catholicism into the heresy which acknowledges neither king nor father. They have also expressed a negative view on the excellence of Western science. Their criticisms of Western science are as follows. Firstly, they have not recognized the academic ability of Westerners. They scorned, exaggerated, and abused Western knowledge as ‘one-sided wisdom’ at best. Secondly, they have looked down on the excellence of Western science as a mere handicraft. They considered the excellence of Western astronomy no different than the special abilities of animal and poultry. The sophistication of Western studies was compared to the “delicate handicraft of Japan and Vietnam”. Thirdly, the difference between the Chinese academic and Western skills were compared with that between the fundamental comprehension of the aristocracy and a handicraft of the lower class. Finally, in their view, the difference between the orthodoxy and the heresy is in ‘academic goal’. They pointed out that heresy focuses on the material force as the principal[主氣] and qi(氣) with physical form[形氣], while the orthodoxy focuses on the nature and external necessity[性命] and the moral principle[道理].