The research of high temperature shape memory alloys (HTSMAs) has attracted much attention due to the control requirements of high-temperature drive (>100℃) and overheating warning in high voltage transmission, nuclear power, aerospace, automotive, oil exploration and other engineering fields. Besides the high transformation temperatures and good mechanical and shape memory properties, the thermal stability of microstructures and properties at high temperatures and after cycling transformations is also the important basis for evaluating the practicability of HTSMAs. The dual-phase Ni-Mn-Ga-Ti HTSMAs were chosen because of their good ductility. In this paper, the as-quenched Ni55Mn25Ga18Ti2 HTSMA is prepared and then the specimens are thermal-cycled between room temperature and 480 °C for 5, 10, 50, 100, 500 times. The thermal stability of microstructure, martensitic transformation temperatures and mechanical properties are studied by X-ray diffraction analysis, scanning electron microscopy, simultaneous thermal analyzer, and room-temperature compression analysis. The results show that no obvious changes in the phase structure and microstructure of Ni55Mn25Ga18Ti2 HTSMA are observed after 500 thermal cycles. With the increase of thermal-cycling times, the forward martensitic transformation temperatures are almost remain constant and the reverse martensitic transformation temperatures and the hysteresis run to steady when the thermal cycles exceed 5 times. After 500 thermal cycles, the compressive strength and compressive stain change little and the shape memory strain drops slightly but remains over 1.4%. The Ni55Mn25Ga18Ti2 HTSMA shows high thermal cycling stability.