The invention provides a medium for a discharge plasma extreme ultraviolet lithography light source and an application system thereof, which relates to a medium for a discharge plasma light source and an application system thereof. The invention aims to solve the problems that the existing discharge plasma EUV (Extreme Ultraviolet) light source is low in radiation light power and bad in stability due to the adoption of an Xe medium, and the existing discharge plasma EUV light source system can not adjust and control different gas flow rates. The medium is mixed gas of Xe gas, He gas and Ar gas with a volume flow ratio of (0.2-2): (1-20): (1-20); and the application system of the medium consists of an Xe gas bottle, a He gas bottle, an Ar gas bottle, an Xe gas flow meter, a He gas flow meter, an Ar gas flow meter, a capillary tube, an electrode and a high-voltage pulse power supply. The medium and the application system thereof have the beneficial effects that the output power of 13.5 nm radiation light is improved by 2 percent, and meanwhile, the gas breakdown performance and the output power stability of the radiation light are improved. The medium is used for the discharge plasma extreme ultraviolet lithography light source.