Chemical changes of the aroma components in green tea during both the firing process and storage under different conditions were investigated. Pyrazines, pyrroles and furans were produced in the firing process. These components were considered to be important volatile substances for the formation of the firing aroma of green tea. Mechanisms of formation of pyrazines and pyrroles produced in firing process were also discussed. The amount of off-flavor components in green tea such as 1-penten-3-ol, (z)-2-penten-1-ol and two isomeric 2,4-heptadienals, increased remarkably during the storage at 25 degrees C. Nitrogen packaging and cold storage were effective for the preservation of the fresh aroma of green tea. Bovolide, pentanal, (E)-2-heptenal and 1-octen-3-ol were identified as off-flavor components of green tea photochemically produced