High temperature platinum resistance thermometers(HTPRTs) were designed and fabricated using a synthetic sapphire single crystal as sensor former, insulation and protection tube, and its characteristics was investigated. Several fixed points measurement showed that the sapphire HTPRTs were satisfied with the ITS-90 criteria as the interpolating thermometer. The temperature-resistance characteristics of HTPRT was fitted to the quadratic relationship in the temperature range from 500℃ to 1500℃. The reproducibility of Cu freezing point realized using the sapphire HTPRT was ± 19.2 mK. The insulation resistance of the HTPRT exponentially decreased as temperature increased, and showed to 63 ㏀( 31.5 mK) at 1500℃.