Abstract: Yi mountains lying in the eastern of middle shandong hill district has now 886 species of seed plant belonging to 122 families and 463 genuses auording to the many years incestigation. The research into 727 species of wild seed plant belonging to 108 families and 411 genuses in flora indicates that the area has typical characteristios of deciduous broadleaved forest in the warm temperate zone, complex geographica compenent, a great variety of flora types, very obvious preponderant phenomena and remarkable character of temperate zone. lompare with neighboring seed plant flora shows:yi mountain and tai mountain have upper homopeneity, itnand lao mountain, yuntai mountain as well as qian mountain is degressive in turn, and it is very different from ruya mountain and daqing mountain.

Key words: Yi mountain of Shandong Province, seed plants flora