In order to obtain high damping capacity within wide temperature window by enlarging the transformation temperature window of NiTi shape memory alloy (SMA) during constraint transformation, an in-situ NbTi-NiTi composite was prepared by vacuum induction melting, hot forging and cold rolling processing. The complete and incomplete constraint transformation damping behavior of the composite was studied by a low-frequency mechanical analyzer LMA-1 testing system. The results show that the predeformed samples can exhibit high damping capacity with in a very wide temperature range, and both the peak temperature and the width of the internal peak increase with the pre-deformation level increasing. In the first heating process, the internal friction peak shows a higher peak temperature and a wider peak temperature range than that of the second heating. During the second heating process, the internal friction peak temperature decreases and the range of the peak becomes narrower than that of the first heating process. The relative modulus curves show the same variation trend. Furthermore, a stepped increasing of relative modulus curve and a peak splitting of damping curve which exhibits the temperature memory effect observed in incomplete constraint transformation.