Latin dance is a partner dance, in which howthe leader leads the follower influences the fluency and cooperation of the dance. This paper, by giving an analysis on biomechanics theories, states that the efficient leading between two partners should be realized by reasonable movement of the barycenter line. By analyzing barycenter leading technique, the paper presents a clear explanation on permission leading, limb leading and hint leading. Research shows that in partner dance, the man should be the leading part while the woman cooperates with him; leading only by arm often results in loss of balance of the lead or the partner; when one is leading with longer steps, postures of two dancers are often inconsistent; leading by the barycenter of the body can effectively avoid losing balance and provide a fluent and coordinate dance; this paper also points out that a good leading is virtually the passing process of the momentum of the body barycenter. This paper does away with old methods used to study Latin dance, which are artistically and aesthetical. It analyzes the leading techniques in Latin dance by biomechanics theories in a natural science perspective while proving the correctness of the dance and provides suggestions.