Hydrogen peroxide (H₂O₂) is an essential molecule in intracellular signaling transduction and normal cell functions. It is critical to be able to detect H₂O₂ quantitatively in cellular processes for getting useful physiological information. Herein, we developed a novel fluorescent probe for H₂O₂ sensing, CePO₄:Tb colloidal solution. Upon addition of H₂O₂, the luminescence of the colloidal CePO₄:Tb solution responds linearly in a wide H₂O₂ concentration range of 0–200 μM, allowing for quantitative detection of H₂O₂. The H₂O₂ sensing by this method exhibits a rapid response within several minutes, a detection limit of 1.03 μM H₂O₂, and a relative standard deviation lower than 3.1%. This sensing material for H₂O₂ is also suitable for the detection of glucose since H₂O₂ is generated via the catalytic oxidation of glucose by oxidase enzymes. In addition to a wide linear response, a low detection limit and a high reproducibility, our present method for glucose sensing shows a highly specific response to glucose in a mixed carbohydrate solution due to the specificity of glucose oxidase to glucose. This lanthanide-based fluorescent sensing material might have potential for detecting H₂O₂ and glucose in biological applications.