The effect of femtosecond laser fluence (0Ф44.2J/cm2) on recast layer and machining eff iciency were investigated with the no-melting ablation threshold (Φth1) and melting ablation threshold (Φth2) in a single-crystal nickelbased superalloy. For the laser fluence range (Φth1ΦΦth2)

there are no indications of conventional laser-induced recast layers in laser-machined area of nickel-base superalloy. For the laser fluence ΦΦth2

recast layers appeared gradually and increased with increasing laser fluence. The relationship between ablation depth for single pulse and laser fluence is established. The larger ablation rate is associated with higher laser fluence.