For optimizing hydraulic absorbers energy absorbing, weve studied the effects of the velocity point (Vmax), the valves opening gate (V0), the stage after the valve is open and the hysteretic lag. The equations of the F-V history curve and the F-S curve at the stage before the valve is open (T1) and after the valve is open (T2) were set up. When Vmax was bigger, T1 was shorter and the displacement of the opening gate (S0) was smaller. But S0 was approximate to A. If we advanced V0, S0 would be smaller, but S0 was was still close to A and it might cause an abnormal vibration. The F-S curve was an ellipse curve at T2. The area of this ellipse was close to k2, but the plumpness degree (φ) was a constant. The damping forces hysteretic lag would induce the F-S curves un-plumpness and over-plumpness. The un-plumpness is more severe than the over-plumpness. It is proper to use the opening gate instead of Φ to describe the damping forces hysteretic lag.