In this study, to develop highly sensitive radiation sensors, $CaSO_4$ : Tm phosphors and its disc-type TLD elements embedded PTFE(polytetrafluoroethylene) are fabricated. The highest sensitivity of $CaSO_4$ : Tm phosphors is obtained when phosphors have been doped with 0.5mol % Tm and sintered in atmosphere at $600^{circ}C$ for two hours. Fabricated disc-type elements are made from a homogeneous mixture of phosphors and PTFE powder. They are first cold-pressed and then polymerized at $370^{circ}C$ in air for one hour. The dose dependence of the prepared $CaSO_4$ : Tm TLD radiation sensors is linear within the range of $100{mu}Gy{sim}10Gy$ for X-rays and ${gamma}-rays$. The response of $CaSO_4$ : Tm to 30keV X-rays is ten times higher than that of 1.25MeV $^{60}Co;{gamma}-rays$. The fading rate of the main peak is about 2% per a month. The spectral peaks of TL emission spectrum are at about 350nm and 475nm. The $CaSO_4$ : Tm TLD radiation sensors prepared in this work may be used as radiation dosimeter for personal and environmental monitoring because of their high sensitivity and little fading.