The real trajectory of V belt is not a theoretic arc due to deviation of circumferential friction from tension of the belt. Three techniques for measuring the belt trajectory during V-belt drive course were proposed; also the accuracy and the operability were analyzed. The range sensor was applied to measure the real trajectory of different speed V belt. The purpose was to provide effective approaches for acquire the real trajectory of V belt, and furthermore, the accurate calculation of the slope angle γ and equivalent coefficient of friction μ-V.