In this paper, the process of ablative gold foil at different energy densities of single pulse femtosecond laser is studied.The interaction between electroacoustic interaction and femtosecond laser ablation under different energy density is discussed， and the correlation of the energy density with the femtosecond laser ablation is derived from the simulated data of the twotemperature model under the finite difference method. Combining the simulation results with the experimental results, the femtosecond laser energy density is the main factor for the processing efficiency and processing quality of the gold foil, which indicates that the femtosecond laser energy density has great significance for the study of femtosecond laser ablation materials.