To address the difficulty in controlling groove depth and roughness during micron-level groove machining of dry gas seals， a theoretical evaluation method was proposed， and a model was constructed to investigate the machining depth and roughness. Using this numerical simulation， the relationships between the laser fill spacing S and spot diameter ds， and the resulting groove depth ha and roughness Ras were systematically investigated. The results demonstrate that the groove depth and roughness decrease with the increasing filling spacing， and the influence on groove depth and roughness is significant when S < 7 μm. The effect of spot diameter on the groove depth is insignificant， the roughness initially increased slowly and then rapidly with the increase in spot diameter， and the critical value of ds was approximately 7 μm. The experimental results well supported those of the numerical analysis of groove depth， which was slightly different from the results of roughness analysis. In this study， the TOPSIS comprehensive evaluation method was used to optimize the optimal range of the processing parameters： considering the processing efficiency， the optimal parameter ranges are 8 μm ≤ S ≤ 15 μm and 9 μm ≤ ds ≤ 15 μm； however， when the processing efficiency is not considered， the optimal parameter ranges are 5 μm ≤ S ≤ 10 μm and 5 μm ≤ ds ≤ 15 μm. The research results have certain guiding significance for further improving the high efficiency and precision machining of micron-level groove depth of dry gas seal.