To optimise the mechanical performance of a buton-rock-asphalt (BRA)- modified asphalt mixture with basalt-fibre (BF), the optimum contents of BF and BRA, as well as the optimal asphalt stone ratio were obtained using response surface methodology (RSM). The feasibility of the mixed-ratio optimised design method was verified via a Marshall stability test. The results indicated that the optimal BF, BRA and asphalt stone ratios were 0.324 %, 22.44 % and 5.23 %, respectively. Moreover, there were some deviations between the average and predicted values of each response index. However, the error range was less than 5 %. A pavement performance index paired comparison matrix calculation method was established, and the pavement performance of the BF-BRA modified asphalt mixture was evaluated using the analytic hierarchy process (AHP). The process comprised eight different content combinations of BF and BRA. The maximum values of dynamic stability, bending strain, immersion Marshall residual stability, and tensile strength ration of BF-BRA modified asphalt mixture were 6512 cycles/mm, 4091 με, 97.4 %, 96.2 % respectively. This indicated that the pavement performance of asphalt mixture can be improved effectively by adding BF and BRA. Additionally, the BF-BRA modified asphalt mixture, which scored highest in pavement performance as evaluated by AHP, aligned with results obtained through response surface methodology(RSM) optimization. This consistency indicates that the BF-BRA modified asphalt mixture derived from RSM exhibits the best pavement performance.