The aim of this study is to understand Lonergan's conversion through his concept of God, anthropology, theology and theological methods. Devoted to teaching and doing theology, Lonergan noticed an unceasing inner motive, pushing people to explore the "known unknown." In the process of experience, understanding, judgment and decision, people make efforts to achieve intellectual, moral, and religious self-transcendence. The love of God floods human hearts through Holy Spirit to guide people to convert. The aim of theological study is to know God. The linchpin of Lonergan's theological thought is conversion, which is also the key point of Method in Theology. With theologians' conversion in intellectual, moral, and religious aspects, the experience of conversion can be objectified and investigated. Through transcendental precepts of being attentive, intelligent, reasonable, and responsible, people achieve authenticity and conversion experience can be the foundation of renewal theology.