Abstract: Anatomic investigation of the brain of Lipotes vexillifer Miller based on three specimens from the Yangtze river has been conducted. The Lipotes brain exhibits typical cetacean characteristics. In comparison with marine odontocetes, the optic system of Platanistidae manifests a regression which is the result of ecological adaptation. From the neuroanatomic standpoint, the brain of Lipotes is similar to that of Inia and Pontoporia, but it is more differentiated than that of Platanista. This conclusion is in accordance with the result of phylogenetic study based on skeleton morphology.