The objective of this work is to investigate the influence of measuring frequency on the internal friction of Ti50Ni48.5Fe1.5 shape memory alloy. The DSC, DC electrical resistivity and internal friction measurements were employed to characterize the sample in this study. Comparing the DSC result, the two internal friction peaks were confirmed which are corresponding to the R-phase transformation and martensitic transformation of Ti50Ni48.5Fe1.5 alloy during the cooling process, respectively. The height of internal friction peak corresponding to martensitic transformation increased with decreasing of measuring frequency. But, the height of the internal friction peak corresponding to R-phase transformation exhibited little measuring frequency dependence. Meanwhile, the value of the relative modulus peaks of the specimen increased with measuring frequency increasing. Furthermore, there was an interesting phenomenon that the martensitic transformation finish temperature shifted to higher temperature side with increasing of measuring frequency. It could be associated with the variation of applied vibration energy.