The flow rate of N₂ had a significant impact on the structure and performance of CrAlYN coatings， so this study systematically investigated the influence of N₂ flow rate on the structure， mechanical properties， and thermal stability of CrAlYN coatings. The results show that as the N₂ flow rate increases from 23 mL/min to 38 mL/min， the nitrogen content in the coating increases from 26.45 at.% to 52.20 at.%. When the N₂ flow rate is 33 mL/min， the nitrogen content in the coating is 49.00 at.%， and the elemental composition conforms to the stoichiometric ratio. The coating has the highest hardness and resistance to plastic deformation. XRD and TEM analyses show that coatings with low N₂ flow rate has a nanocrystalline structure and lower hardness. The coatings with high N₂ flow rate has a columnar crystal structure， and the injection of nitrogen atoms increases the compressive stress of the coating and reduces its hardness. The coating with a N₂ flow rate of 33 mL/min has smaller grains and a dense structure， with a hardness of 24.6 GPa. After annealing at 1 000 °C， the coating shows slight oxidation and a hardness of 18.4 GPa， which is higher than that of coatings with other N₂ flow rates， indicating that this CrAlYN coating has the best overall performance.