In order to realize the industrial application of high-current pulsed electron beam on material surface modification, it is necessary to monitor tiny perturbation in real-time. The electric field strength is a critical parameter understanding the characteristics of electron beams. The laser-induced fluorescence-dip spectroscopy method based on the Stark effect can realize the tiny perturbation measurement of electric fields. Therefore, Studying laser power density influence on the electric field has significant theoretical and application value for the parameter setting and result interpretation of similar electric field measurement methods. The theoretical analysis and calculation are used to obtain the relationship model between excitation laser power density and the test environment parameters in the tiny perturbation state of electric field measurement. Then, based on the above relationship model and theoretical calculation, the influence of excitation laser power density on electric field measurement is verified experimentally. The experimental results show that under the conditions that the tracer gas xenon pressure is 1.0×10^-4 mbar and the electric field strength is 2 kV/cm or below, the excitation laser power density of tiny perturbations on the electric field measurement is 5 MW/cm², which is consistent with the theoretical calculation value. The research results provide a quantitative analysis method for studying the influence of laser power density on the electric field in the laser-induced fluorescence-dip spectroscopy. They can be applied to similar electric field measurement methods, open the way for the setting of laser power density and experimental parameters, support the development of electric field measurement experiments, and effectively improve the accuracy of electric field measurement.