This paper introduces the basic classification of Ondol, the number and form of main entrance, distribution as a basis for classification. And it introduces the various practices and structural characteristics of Ondol. Details are introduced in various forms Ondol of the working principle. In the paper, it also did a more detailed exposition for some of the concepts right.

Abstract
 1. Purpose of the study and term definition of Ondol
 2. Word’s definition of Ondol
 3. Classification of Gorae Ondol(Gudle)
  3.1. Classification by Forms of Gorae Ondol(Gudle)
  3.2. Classification by position and number of Gorae Ondol(Gudle)
  3.3 Classification of ‘Gorae Gudle’ by Agungi(fire hole)
 4. Conclusion
 References

• Jungbong Kim(Dept. of Architecture, Beijing University of Technology)
• Younsook Hwang(Gansam Architects Group)
• Ying Wan Wu(Dept. of Architecture, Beijing University of Technology)