Laser-Sustained Plasma (LSP) has been widely used in semiconductor wafer defect detection by realizing electrode-free energy coupling through the inverse bremsstrahlung absorption mechanism, which has the advantages of wide spectral range, high brightness and long lifetime. To further clarify the microphysical mechanism of LSP, the dynamic evolution law of high-pressure xenon LSP and the spatial distribution of its electronic parameters were systematically investigated by high-speed imaging and spectral diagnostic techniques. The results show that the plasma morphology shows axial expansion dominated “droplet-like” evolution with the increase of laser power. The position and intensity of plasma centroid oscillate at a specific frequency, and the frequency of the oscillation decreases with the increase of laser power. The electron density and electron temperature in the plasma core region increase by 34.2% and 4.3% with the laser power increasing from 60W to 120 W, respectively. However, the electron parameters show a saturating trend or even a slight decrease with further increase in laser power.