<p>In this paper, a systematic and innovative study on arc enhanced glow discharge (AEGD) plasma nitriding process was carried out to achieve the optimization of nitriding effect and the significant improvement of coating properties. Through the design and implementation of multiple comparative experiments, the influence of auxiliary anode layout and output mode on the nitriding process was systematically investigated, and the mechanism of nitriding layer on the performance of AlCrN coating was analyzed. The research is conducted through a complete research loop involving basic process optimization, parameter refinement, and engineering application. The results show that the auxiliary anode layout significantly affects the nitriding uniformity. Compared with other layouts, the PN-C layout shows better overall performance while improving the nitriding uniformity of samples at different height positions. The structure and properties of nitriding layer were precisely regulated by auxiliary anode output mode modulation technique, and the nitriding effect of each sample showed a significant difference of PN₄ &gt; PN₃ &gt; PN₂ &gt; PN₁. In addition, the nitriding layer provides a strong support for the AlCrN coating. With the improvement of the nitriding effect, the prepared PN₄ + AlCrN composite coating shows more excellent load resistance and high temperature resistance.</p>