Abstract: With the depletion of shallow surface metal mineral resources, China's underground metal mining was gradually transferred to deep mining (>1 000 m).Because of the special mining conditions of high stress, great lifting depth, and high temperature in deep mines, it is difficult to realize the safe, efficient, and economical exploitation of deep resources by using the traditional mining methodology.According to the trend of deep metal mineral resources, a novel idea of in-situ fluidization mining for deep metal mines was proposed.The definition, conception, and challenges were introduced.According to the transformation methods, in-situ fluidization mining can be divided into two parts: in-situ leaching mining, and integration of mining, processing and backfilling.Moreover, the major issues and challenges faced with in-situ fluidization mining, namely, deep rock mechanics, in-situ leaching mining theory, equipment of integration of mining, processing and backfilling, environment monitoring and reconstruction, intelligent and efficient mining, were expound.