This paper discusses the way in which Yi Hang-No, one of the leading conservative Confucian scholars in the mid-19th century Korea, dealt with the intellectual challenges thrown by Western science and technology. Depending on fragmented and secondhand knowledge on Western science, he criticized it by mobilizing the rich traditional resources, at the kernel of which lay the neo-Confucian metaphysics and natural philosophy. In his scheme, Western science, though he admitted it was impressively exact, considered as humble and subversive entity representing the category xingqi(形氣), whereas the neo-Confucian metaphysical learning was linked to more noble category daoli(道理). For example, facing the attack of the concept of spherical earth to the traditional belief on China as the center of the earth, Yi criticized it as a superficial view inclined to the xingqi aspects of the world. On the contrary, he argued, through the eye of daoli one could see the profound and qualitative distinctions in the world. In Yi's view on Western science, we can find his sharp insights into the unauspicious omens of the destructiveness of modern science. However, his way of dealing foreign learning was essentially the same as those of the 'orientalists' in the 'West' of that time: The construction of the 'Western science' in order to control it.