Visuddhimagga is one of the most influential texts in Theravada Buddhist tradition. Its said author, Buddhaghosa, is reported to have gain the trust of monks at Mahavihara upon the completion of the Visuddhimagga and subsequently was entrusted with the works of translating Pali manuscripts by Mahavihara monks. Because of his efforts, Pali canons were persevered. In the Visuddhimagga, ways of Theravada practices are clearly laid out and provide a systemic discourse on Theravada spirituality and doctrine. It helps to formulate Theravada tradition. Many modern scholars also have great praises for this book. The first chapter of this essay will introduce research motivates, research goal, research structure and literature review. The second chapter will discuss the development of Theravada tradition and life of Buddhaghosa in order to have a better understanding of the context behind the compilation of the Vissuddimagga. The focus of chapter 3 is on the structure of the Vissuddimagga, on how the Vissuddimagga delivers Theravada doctrine and spiritual path. Chapter 4 will analyze the main theme of this research, brahmavihara-niddesa. I will discuss the origin of the brahmavihara-niddesa concept and how it might be applied to spiritual practice. Chapter 5 will discuss the bodhisatta path as it is presented in Theravada tradition; it is sometimes assumed that Theravada tradition does not contain the concept of the bodhisatta path and chapter 5 is an attempt to examine this misconception. Chapter 6 is the conclusion chapter, focusing on the discussion of the relationship between the Brahmavihara-niddesa and the bodhisatta path. I wish that through this research, I may gain a better and more systematic understanding of the Brahmavihara-niddesa.