Abstract: There are close relationships between velocity pacing and performance of time trial sporting events.Reviewed on the current researches, this paper categorized the common used pacing profiles in the competitions into 6 types:all-out pacing, positive pacing, negative pacing, even pacing, parabolic-shaped pacing and variable pacing, furthermore discussed the characteristics and application of different pacing types in terms of energy metabolism.The result showed that the purpose of adopting the velocity pacing was to use the kinetic energy reserve as much as possible, sports fatigue theory couldn't explain why changes of velocity took place during the competition clearly, velocity pacing might be regulated by athletes with the perceived exertion based on the complex connections among the physiological, psychological, training and competition experiences, etc.