A detection system using luminescent bacteria revived from freeze-dried powder as biosensors. Luminescent bacteria emit light during metabolism, and if the metabolic process is affected, it can lead to changes in luminescence intensity. Toxic substances in water samples can inhibit metabolic processes, and the toxicity of water quality can be evaluated by measuring the decrease in luminescence intensity after contact between luminescent bacteria and water samples. This method is applicable to the determination of surface water, industrial wastewater, and domestic sewage.