In this paper, we collect the 37 years’ data observed for BL Lac object OJ287 in the optical band, and construct its light curve from 1972 to 2009. Using the method of Lomb-Scargle Fourier transform, we analyze the middle time-scale periodic behavior and discover the primary periodic compositions of 52.0 ± 1.1 day and 255 ± 23 day. Then, we simulate the quasi-periodic signal of period doubling bifurcations and compare it with the observation data at different time-interval in their phase diagram and correlation dimension. Result indicates that OJ287 has multi-period scale features. At different time-intervals, there are different harmonic period components in the quasi-periodic light curve. Variation of harmonic period component is related with the disturbance of accretion flow which is from the secondary black hole to the primary black hole, and the periodicity variability may bifurcate the harmonic period component when the primary accretion flow is influenced by a strong disturbance.
OJ287 光变周期 吸积流 倍周期分岔