Dy doped strontium aluminate phosphor (SrAl4O7:Dy(15% molar concentration)) was synthesized by combustion method using urea as a reducer at initiating temperature of 600oC. The absorption spectra shows the absorption edges at l = 242 nm, thus the band gap of 5.11 eV. The Thermoluminescence (TL) property of Dy(15%) doped SrAl4O7 nanophosphor has been investigated for l-irradiation. The TL glow curve of SrAl4O7:Dy (15%) phosphor with different ?-ray doses show the dose increases the TL- intensity while the temperature corresponding to maximum intensity remains nearly same. The maximum TL-intensity observes around 172.84 oC for the different doses. It was found that TL intensity strongly depends upon the -dose. It shows linear response upto 2.36 kGy. Hence Dy(15%) doped SrAl4O7 could be used for TL Dosimetry upto 2.36 kGy.