The knowledge of the Buddhist theory was widely spread on too many sutras. And each of them has their own main theoretical concern. On the appearance different sutras maintain different theories. But in fact different theories should be integrated into a united theoretical system. This is the author's attitude toward the way of the Buddhist study. Therefore there must have a way to do this study. The author tries to provide an analytical structure to help to understand the individual knowledge appeared on each separated sutra. And try to integrate the separated knowledge into a united theoretical system. In order to open this study the author starts to interpret the individual sutra's important knowledge in the way of analyzing its statement's meaning and theoretical connection. In so doing, this article will try to focus on one Mahayana sutra to tell its important knowledge. The Lankavatara Sutra is one of the most important sutras in Chinese Zen Buddhist School. There were really many important Buddhist theories presented in it. In this article the author tries to discuss the following issues: the knowledge meaning of the concept of "Five Dharma (五法)"; "Tathagatagarbha (如來藏)"; "The highest wise (第一義)"; "Self evident confines (自證聖智境界)"; "Body by mind (意生身)"; and the idea of "Buddha will necessarily confirm the bodhisattva become another Buddha in the future (佛必為菩薩加持)"; "Three vehicles become one (三乘一乘)"; "Buddha never stay in Nirvana (佛不入涅盤)"; "The benefit of the Vegetarian (素食功德)"; "Buddhist learning through the way of direct practice or theoretical construct (宗通與說通)".