Abstract: By using document literature and other methods, this paper tries to explore the essence of Taijiquan from the theory of Qi.After analyzing the three stages of Taijiquan practicing in this way, we find that the gain of first stage (mastering movements) is to seek the congenital physical and mental consciousness, the gain of the second stage (understanding force) is to feel the inside cohesive flow of Qi and the gain of the third stage (illuminating mind) is to reach the clear and natural state.The three stages are all based on Qi which plays a very important role in Taijiquan practicing.The essence of Taijiquan can be concluded as an approach of "the flow of Qi" and "the turn of Tao".