SrSO4 (strontium sulphate) has been prepared by the chemical precipitation technique and characterized by XRD and TEM (Transmission Electron Microscopy). TEM shown the formation of compound in ring like structure with average particle size 45 nm. The erbium (Er) doped to SrSO4 by different concentrations for the sake of improving the TL-sensitivity of SrSO4, were found the optimum concentration of erbium is (22wt%). SrSO4:Er (0.22wt%) has five glow peaks at (116.5 ˚C – 183 ˚C – 344 ˚C – 412 ˚C – 431 ˚C). High gamma doses as TL-sensitization method have been used. By these means the TL-intensity of treated samples proved about 30 times enhancement, which make it very promising detector and dosimeter suitable for ionizing radiation.