以合金钢为样品，利用Cr I 520.8 nm和Fe I 522.7 nm谱线强度变化分析预烧蚀激光参数对纳秒532 nm/1064 nm正交预烧蚀双脉冲激光诱导击穿光谱（DP-LIBS）增强的影响，对实验条件进行了优化。结果表明在预烧蚀脉冲能量为70 mJ，主烧蚀脉冲能量为100 mJ，预烧蚀脉冲焦点距样品表面1 mm，距主烧蚀脉冲光路1 mm时，DP-LIBS具有最大光谱增强。Cr I 520.8 nm谱线在30 μs时光谱增强达到12.5，然后快速下降。最后初步分析了正交预烧蚀DP-LIBS光谱增强机理。

Effect of pre-ablation laser parameters on the spectral enhancement of 532 nm/1064 nm orthogonal pre-ablation dual-pulse laser induced breakdown spectroscopy (DP-LIBS) is analyzed by the spectral intensity variation of Cr I 520.8 nm and Fe I 522.7 nm for the alloy steel, and the experimental conditions are optimized. The experimental results show that DP-LIBS has a maximum spectral enhancement at the conditions of the pre-ablation pulse energy of 70 mJ, the main ablative pulse energy of 100 mJ, the distance of focus point of the pre-ablation pulse to the sample surface of 1 mm and to the main ablation pulse light path of 1 mm respectively. The spectral enhancement of Cr I 520.8 nm is 12.5 at interpulse delay time 30 μs, then decreases rapidly. Finally, the spectra enhancement mechanism of orthogonal pre-ablation DP-LIBS is analyzed.