A predictive correlation of effective hydrogen to carbon ratio ((H/C)eff) of bio-oils was satisfactorily developed to describe the general trends of bio-oil quality in fluidized beds of lignocellulosic biomass pyrolysis for production of bio-oils compatible with petroleum refinery. The correlation was based on an empirical relationship with operating parameters including fluidization hydrodynamics in fluidized bed pyrolyzers, which was derived from the data of this study and literature. The increment of (H/C)eff from feedstock to bio-oil during pyrolysis was a strong function of fluidization variables related with hydrodynamics and bed mixing such as fluidization number, bubble fraction and entrainment flux of bed materials. The predicted (H/C)eff of bio-oil based on the correlation well accorded to the experimental data. The prediction results indicate that the correlation can predict an optimum operating condition for balancing quality against bio-oil yield.