Human beings are remarkably sensitive to recognizing the motion of biological entities in complex visual scenes, even when it is depicted with a handful of point-lights attached to the head and major joints. A number of studies demonstrated that biological motion contains not only form and motion information, but also include many sorts of socially relevant information about an agent such as identity, gender, emotions, intentions and so on. The ability of human observers to identify gender is a well-known and often cited result in the perception of biological motion. But till today, the topic of the researches about the gender perception of biological motion is the influence factors of the perception process. And there are two approaches have been advanced to explain the ability of observers to recognize gender from point-light displays. The first of these emphasized the role of gender differences in the shape of male and female bodies as indicated by hip and shoulder dimensions. The second of these emphasized the role of gender differences in the motion of male and female bodies as indicated by he lateral sway of the hip and shoulder. But recently, researchers have found that there exists obvious adaptation aftereffects in the gender perception, and the auditory also could effect gender perception. These results suggest that not only the bottom-top information may influence the gender perception, but also there exists top-down processing that regulate the gender perception. However, how the top-down information influence the gender perception is unknown. Many researches have found that anticipatory mental imagery has the power the anticipate and fill up the detail information when the input information is absent or lack detail information to identify. Evidence from brain imaging studies suggests that expectations have the power to alter perceptual judgment, affective responses and neural processing in various stimulus modalities, including gustatory processing, olfaction , vision, kinesthesia, and pain. In this article we investigated how top-down information influence gender perception of biological motion with two experiments: one is group with anticipatory mental imagery and the other not. In the imagery experiment, the observers are asked to imagine the person who is with obvious gender feature follow the name. There are three names here,female name, gender neutral name and male name , the names are all well known to the participants. The non-imagery group only received the general instructions (i.e., information about the meaningless characters, the trial structure and the general purpose of the study) and then carrying out mathematical calculations following the names. There are also three meaningless characters here. The results found that the anticipatory mental imagery of man according the name could speed up the response of the perception of male biological motion. The results indicate that the anticipatory mental imagery could alter gender perception of biological motion, and there may exist the man bias which influence gender perception of gender neutral biological motion.This study is helpful to reveal how the anticipatory mental imagery alter the psychological mechanism of gender perception of biological motion.