Abstract: With self-made high-purity Y₂O₃ powder as raw material, Y₂O₃ coating was prepared on the surface of A6061 aluminum alloy substrate by atmospheric plasma spraying. Based on the response surface methodology, the corresponding response surface maps were constructed, and the influence of the interaction of spraying voltage (60-80 V), spraying current (500-600 A) and spraying distance (100-120 mm) on the microhardness and porosity of the coating was analyzed. The plasma spraying process was optimized. The results show that a quadratic mathematical model of the microhardness and porosity of coating was established by response surface methodology. The optimal process parameters of the Y₂O₃ coating predicted by the model were listed as follows: spraying voltage of 78 V, spraying current of 500 A and spraying distance of 120 mm. The corresponding microhardness and porosity were 633.28 HV and 3.22%, and the relative errors of the predicted value and the test value were 1.92% and 1.26%, respectively, verifying the accuracy of the model. Under the optimal process, the surface roughness of the prepared coating was 5.733 μm, and the bonding strength was 25.6 MPa.