The O III (4959, 5007) lines from spectra of Mrk 817 obtained from a 9-year long period were analyzed. A blue asymmetry of the lines is noticeable. The authors have found that the Narrow Line Region (NLR) of Mrk 817 consists of two subregions (NLR1 and NLR2). NLR1 should be closer to the central source with higher velocity of the emitting emission gas than in NLR2. A model which can describe the O III narrow lines as well as broad Hβ shapes of Mrk 817 should consist the four regions; Broad Line Region (BLR), Intermediate Line Region (ILR) and two NLRs. Also, an outflow of the emitting gas in BLR, ILR and NLR1 as well as gravitational effects in BLR should be considered.