In this paper,in order to understand the interaction mechanism between the ultrafast laser and the material,and to optimize the laser metal ablation ability for an ideal ablation effect,a two temperature model for ultrafast laser ablation is introduced in a two dimensional axisymmetric model.The ablation behavior of the picosecond laser for a low melting point alloy represented on 7075 aluminum alloy is simulated.By changing the power density and impact number of the picosecond laser,the influence of the various parameters on the 7075 aluminum alloy was determined,and the experimental results was compared.The results show that the experimental depth of laser ablation is less than the metal melting temperature layers calculated by the two temperature model,while the ablation depth of the laser is linearly correlated with the power density.When the depth of ablation crater reaches to the certain depth,the laser ablation depth hardly increases with the times of the ablation.