The invention discloses a method for preparing water-soluble light-emitting gold nanoclusters based on a substitution method and aggregation inducement. The method is characterized in that a silver nanocluster template solution is prepared; secondly, the silver nanocluster template solution and chloroauric acid have a substitution reaction to obtain the gold nanoclusters; and thirdly, the aggregation inducing light-emitting effect on the gold nanocluster is achieved. According to the method, preparation is conducted in a water solution at the normal temperature, and the method has the advantages that operation is easy, repeatability is high, cost is low, surface charges and surface property are controllable, functional groups are easy to introduce, and biocompatibility is good. The prepared gold nanoclusters are good in light-emitting stability and have potential application value when serving as biomarkers especially as DNA probes for nucleic acid specific detection.