As a new type of nanomaterials, fluorescent gold nanoclusters are low toxicity, good light stability, and long Storck shift. Based on these excellent properties, they are potentially applied as fluorescence sensors with less interference. These materials have attracted great attentions in the area of environment monitoring. However, due to the high cost and complicated reaction conditions, most methods for synthesizing gold nanoclusters are expensive and are not suitable for wide application. In consideration of the current requirement for more efficient methods for the preparation of fluorescent gold nanoclusters, egg white protein was obtained from market and employed as a green ligand for the synthesis of gold nanoclusters without the utilization of complicated procedures. The nanoclusters could be obtained at 37 ℃ through water bath for 24 h. The procedure was not only effective but also low toxicity during the synthesis process. After the synthesis, highly bright fluorescent gold nanoclusters were obtained. Based on our experiment, the As prepared gold nanoclusters had excellent stability and fluorescence properties. The excitation wavelength for the maximum emission was 470 nm and the wavelength for the emission was 680 nm with a quantum yield of 8.76%. It could be concluded that typical red emitted gold nanoclusters were synthesized, which was favorable for the environment analysis. After further investigation, the As prepared gold nanoclusters could be designed as Hg2+ selective sensor in water solution with little interference. Since the fluorescence could be quenched in the presence of Hg2+ with low concentration, it could be used for the determination of tracing amounts of Hg2+ in polluted water. The detection limit was smaller than 1 ppb, which met the requirement for the determination of Hg2+ for safe drinking water. The relative linear correlation coefficient value for the calibration was larger than 99.8%. Meanwhile, the recovery efficiency for the determination of Hg2+ was investigated. After the comparison with atomic absorption spectroscopy method, it could be concluded that the current method showed advantages for determination of tracing amounts of Hg2+. At the same time, the accuracy was satisfied for the detection of relative high concentration of Hg2+. By the employment of this method, an effective strategy can be expected for the determination of Hg2+ in natural water.