Lithium triborate (LiB3O5) was produced by different synthesis methods, which included high-temperature solid-state reaction, microwave-assisted high-temperature solid-state reaction, and precipitation-assisted high-temperature solid-state reaction. After the synthesis, metal oxides (CuO and Al2O3) were doped into LiB3O5 to enhance its thermoluminescent (TL) properties, and the TL intensities were compared with each other. The identification and characteristics of undoped and doped LiB3O5 were determined by X-ray diffraction (XRD), Fourier transform infrared (FTIR) analyses, differential thermal analyses (DTA), scanning electron microscopy (SEM), and particle size analyzer. The glow curves were obtained by using a TL reader. The results showed that synthesis routes affected the physical and structural properties of lithium triborate, which have an important effect on its TL intensity.