The effect of different anisotropy and stress ratio on fatigue crack propagation behavior was investigated under various stress ratio(R=-0.4, -0.2, 0.2, 0.2, 0.4) using pure titanium sheet used in aerospace, chemical and food industry. The rack closure behavior under constant load amplitude fatigue crack propagation test was examined. Fatigue crack propagation rate da/dN was estimated in terms of effective stress intensity factor range, $Delta$K$_{eff}$, regardless of various stress ratio but was influenced by anisotropy. Also, it was found that the effect of anisotropy was considerably decreased but still not negligible when he da/dN was evaluated by a conventional parameter, $Delta$$K_{eff}$/E and when the modified da/dN.$sqrt{varepsilon}_f$ was evaluated by $Delta$$K_{eff}$/E. On the other hand, da/dN could be evaluated uniquely by effective new parameter, $Delta$K$_{eff}$/$sigma_{ys}$, regardless of anisotropy, as int he following equation da/dN= C"[$frac{DeltaK_{eff}}{sigma_{ys}}$] n". And effective stress intensity factor range ratio, U was estimated by the following equation with respect to the ratio of reversed plastic zone size, $Delta r_{p}$ to monotonic plastic zone size, $r_p$ regardless of stress ratio and anisotropy. U=-4.45$(Delta r_{p}/r_{p})^{2}$+4.1$(Delta r_{p}/r_{p})$+0.245_{p})$</TEX>+0.245