Abstract: The mineralization of the small rock mass is a new academic concept proposed through the exploration and research of metallic sulfide deposit with the magmatic activity by Tang Zhongli,which is a popular characteristic in endogenic magmatic deposits,it is also a key to reveal the principle of metallogenesis for our ore-prospecting work.Here is a new definition and classification have been put forward based on years' studies,including magmatic liquation and magmatic hydrotherrnal.The first tapy was composed of sulfide segregation and oxide segregation; second one was formed with water-hydrothermal metasomatism、filling metasomatism and contact metasomatism.There are four mechanism of mineralization of the small rock mass: deep segregation model,magma conduit model、pulse model and hydrothermal pulse model.Discussed oxygenisotopic composition of hidden and half-concealed igneous rocks and the key factor of discretion in ore-bearing potential of the small rock mass.