Based on tests of pre-enrichment gold in water, the authors chose two known gold mines with different natural landscape conditions and different genetic types in central Inner Mongolia to test the validity of this technology. A gold pre-enrichment method in water was established with polyurethane foam cleaned by hydrochloric acid. A quick and simple field method for gold pre-enrichment in water was developed. It is found that the gold content of water in the dry season is higher than that in the rainy season. Hydrochemical survey should be usually conducted in the dry season so as to guarantee the consistency of the results. Good gold anomalies were detected in the Donghuofang gold mine, the Laoyanghao gold mine and the peripheral Hejiaoyi belt, which shows that the method is effective. In the area of loosen thick overburden, the performance of the water chemistry survey led to the discovery of gold anomalies which could not be found by stream sediment survey and soil survey in the past, suggesting that the method discussed in the paper is useful in search for blind gold deposits.