Abstract: Based on the plane- wave pseudo- potential and generalized gradient approximation，the structure，electric property and optical property of poly- para -phenylene vinylene（PPV）were studied.Analyzed the relationship between the distribution and structure of electronic states. Gave out the density of states and the band structure of system before and after doping of PPV. Under the standard conditions，the atom in PPV cell are in the same plane，the structure constants such as bond lengths and bond angles are consistent between experiment and theory. Replaced the C atom with N atom in PPV，formed poly ppyridyl vinyline（PPyV），after calculating，found out the energy band has slight difference with PPV materials，and the wave form of absorption spectrum are nearly the same，however，obvious blue shift occurs in absorption peak. The results comply with the existing literature.

Key words: poly- para - phenylene vinylene（PPV）, poly p - pyridyl vinyline（PPyV）, density functional theory（DFT）, electronic structure