In order to obtain the physical mechanism of the enhanced spectral performance of the combined pulse laser-induced plasma, the effects of pre-pulse parameters on the spatial and temporal distribution of parameters of the combined pulse laser-induced aluminum plasma were simulated based on the FLASH program. The spatial evolution of electron temperature, electron density, and ablative mass of aluminum plasma under different prepulse wavelength and different pre-pulse delay was obtained. The numerical simulation results show that the space range of helium plasma plume increases from 0.7cm to 3.0cm with the change of pre-pulse wavelength from 0.266μm to 1.064μm when the total energy of the pre-pulse is the same, but the ablation efficiency of the combined pulse on the target decreases seriously. During this period, the maximum electron temperature of the aluminum plasma remains stable. In addition, the combined pulse time delay should be less than 100ns. This study can provide a theoretical reference for combined pulsed laser-induced breakdown plasma spectral enhancement technology.