A series of phosphors Ba0.955Al₂Si2－xGe xO₈∶Eu²⁺ (x=0.0－1.0) w ere prepared via solid-state reaction in weak reductive atmosphere.The lattice positions and the luminescent mechanism of Eu²⁺ in the host are discussed.The effe cts of Ge⁴⁺-substitution on the host lattice and spectral properties are also i nvestigated. The results show that complete solid solution is formed in the whole range of x =0.0－ 1.0while Ge⁴⁺ enters BaAl₂Si₂O_8lattice and substitute Si⁴⁺ .The lattice para meters (a,b,c,β) and unit cell volume of phosphors Ba 0.955Al₂Si2-xGexO ₈∶Eu²⁺ (x=0.0－1.0) increase linearly as Ge⁴⁺ content increases in the phosphors.A broad exci tation spectrum consists of four excitation bands,which locate between 230nm and 400nm,and the maximum emission wavelength is at 332nm.The FW HM of the apparent excitation peak is narrowed from 93nm to 80nm.The broad and asymmetri c emission spectrum is between 375nm and 600nm and apparent peak is at 434nm,wh ich can be fitted by two peaks at 422nm and 456nm.The distance between Eu and O is shortened due to Si⁴⁺ is replaced by Ge⁴⁺.The crystal field of the emitting center Eu²⁺ is enhanced.The splitting of 5d orbital levels is enhanced and the lowest emission level is expanded to lower region,and two fitted peaks are red shifted.