By using the ways of theoretical derivation and simulation experiments, the quantitative relationship between charge collection ability in pulsed laser simulation experiments is studied when single-photon absorption and two-photon absorption are dominant respectively. The effects of different optical parameters on ionizing charge concentration are analyzed in simulation experiments, and specific parameters such as laser wavelength, pulse width, energy and beam spot are determined. According to the characteristics of single-photon linear absorption and two-photon nonlinear absorption of pulse laser in Si, the quantitative formula of the ratio of charge generated by single-photon and two-photon absorption is derived. Through the verification experiments of 1064 nm and 1200 nm laser, it is found that the response pulse and the amount of charge generated have a good linear relationship with the pulse laser energy or energy square, and the charge generated by single-photon absorption is significantly higher than that by two-photon absorption when single-photon absorption and two-photon absorption are dominant respectively. It is proved that the ratio of the charge generated by the two wavelengths is approximately equal to the calculated result. The results show that the amount of charge induced by the 1200 nm pulsed laser 1 nJ² is equal to the amount of charge induced by the 1064 nm pulsed laser 0.039 nJ.