The purpose of this paper is to make a comparative study of the practice theories and methods of “maraṇānussati” in Upatissa’s Vimutti-magga and Buddhaghoṣa’s Visuddhi-magga. First, the researcher clarifies the concept from the following three aspects: the concept of “death” in Buddhism; the concept of “anusati” in Buddhism; and concept analysis combining how “maraṇānussati” is presented in Buddhist classics. The part of “death” in Buddhism is discussed withthe methods of Buddhist text extraction, Pali word interpretation, and original scriptures presentation. In the part of “anussati” in Buddhism, the reason why the title uses “maraṇānussati” instead of “maraṇassati” is stated. Then, the paper analyzes the presentation of “maraṇānussati” in the Tipiṭaka, the Mahā-prajñāpāramitā-śāstra, and the Lamrim Chenmo, as well as expounds the content of “maraṇānussati” in “Caturārakkhā Bhāvanā”. Although the method of “maraṇānussati” in Vimutti-magga is similar to that in Visuddhi-magga, there are many differences in details. There are two types of “maraṇānussati” in both theories, namely “pay attention to the death of others” and “pay attention to one''s own death”. There are two ways of thinking about the death of others: one is the right way (yoniso) and the other is the wrong way (ayoniso). There are eight methods in each of the two theories, of which the researcher will conduct a complete comparative analysis.