Abstract: Under normal pressure and temperature, aluminum alloy in air can be excited by Nd:YAG nanosecond laser with wavelength 532 nm, the collection and photoelectric conversion of the plasma emission spectrum are executed by a high-resolution spectrometer and an ICCD. This paper studies the influences of laser energy, ICCD gate delay and lens-to-sample distance (LTSD) on the spectral intensity and plasma electron temperature as well as the physical mechanism. It is demonstrated that the spectral intensity and electron temperature increase with the increase of laser energy at the fixed ICCD gate delay and LTSD. The calculated results show that when the laser energy increases from 20 mJ to 160 mJ, the line intensities of the atomic spectral lines Al I 396.15 nm, Mg I 518.36 nm, and the Mg II 279.54 nm ion spectral line are 12.83, 6.45 and 10.56 times higher than that of 20 mJ, respectively. At the fixed laser energy and LTSD, when the ICCD gate delay changes within 100−4 000 ns, the spectral intensity and plasma electron temperature decay exponential with the increase of ICCD gate delay. With the same ICCD gate delay and laser energy, the influence mechanism of LTSD on plasma parameters was studied by using a focusing lens with focal length of 75 mm. It is demonstrated that the lens-to-sample distance has a considerable impact on the spectral intensity and plasma electron temperature. The results indicate that the change of the spectral intensity is consistent with that of the plasma electron temperature. The curves have two peaks at the distances of 73 mm and 79 mm from sample surface, and the values reach their maximum at 73 mm.