Geothermal systems with crustal magma chambers as a primary heat source have been a research hotspot in the international geothermal community.Controversially, there is still no exact definition of these geothermal systems strongly affected by underlying crustal magmas. This article deals with a discussion of the relationship between a strictly defined magma- impacted geothermal system and its underlying magma chamber(s), an explanation of the mechanisms involved in the formation of various magmatic heat sources and the nature of their influences on overlying geothermal systems, and a review of the common ways to evaluate the quantitative contributions of magmatic fluids to overlying geothermal waters based on their geochemical compositions. Combining the insights mentioned above, a magma- impacted geothermal system should be referred to as a system with very high reservoir temperatures due to conduction of magma heat and direct input of magmatic fluid.