The second harmonic of a pulsed Nd∶YAG laser (532 nm) has been used for the ablation of aluminum alloy in air at atmospheric pressure and the laser-induced plasma characteristics were examined in detail.The electron density of 4.3 × 1016 cm3 was inferred from the Stark broadening of the profile of Fe (Ⅰ) 381.59 nm,while the plasma temperature (8405 K) was obtained using the Boltzmann plot method of nine neutral iron lines.The calibration curve for iron was established using a set of six samples of standard aluminum alloy.The plasma was verified to be optically thin and in local thermodynamic equilibrium based on the experimental results.