The deposits related to granites are mainly magmatic—hydrothermal ores, of which their time—space distribution and genesis display great intimacy with the associated granites. Whether it can exsolve hydrothermal fluids during magmatic melting and what quantity of exsolutions it can provide is becoming a necessary prerequisite that constrain granitoid mineralization. Based on the previous researches and study here, this paper systematically summarizes that granite related to mineralization develop petrological structure of unidirectional solidification texture (UST), quartz eyes, miarolitic cavities and snowball texture in the exsolution and saturation of magma volatile phase. Contribution of magmatic chemical composition to the evaluation of ore potential of granites based on elemental geochemical behavior and physical—chemical conditions. The halide content in volatile components and the abundance of major elements cannot be used as discriminative indicators of mineralization potential, while trace elements are geochemical fingerprints that identify the ore potential of granites. The characteristics of high field strength elements and rare earth elements showing changes in system geochemical behavior are expected to be the best indicators of mineralization potential. These informations provide theoretical guidance for the metallogenic prediction and prospecting evaluation of magmatic—hydrothermal polymetallic deposits. Moreover, this paper also presents the problems in the study and points out the work that needs to be done in in near future.