Phosphate glass samples with different doped lanthanum concentrations were prepared. The samples were subjected to XRD investigation. The given thermoluminescence glow curves of the samples were analyzed and exhibited a superimposed of five glow peaks at 386.7, 422.4, 461.6, 488.8 and 510.3 K. The activation energies of the corresponding electron traps were defined with their frequency factors and their lifetimes. The dosimetric properties of the glass doped lanthanum as beta dosimeters were investigated like dose response linearity, dosimetric sensitivity, reproducibility, minimum detectable dose and signal stability were done as well.