Most high temperature absorbing materials belong to non-magnetic loss type， and it is difficult to achieve ideal absorbing properties in single layer. In order to solve this problem and optimize the coating thickness， a multi-objective optimization model of multi-layer high-temperature absorbing coating was established by differential evolution algorithm. The reflectivity RL<-10 dB frequency bandwidth and total coating thickness in the range of 8.2 to 12.4 GHz were taken as the optimization objectives. In this paper， three kinds of high-temperature absorbing materials were set up. And the result shows that it is difficult for single-layer coating to achieve the ideal absorbing performance. In the single-objective optimization， the frequency bandwidth is taken as the optimization objective， and it obtains the effective bandwidth is 3.2 GHz， and the wave absorption performance is improved. In the multi-objective optimization， the total coating thickness is optimized at the same time. Compared with the single objective optimization， the coating thickness d decreases by 30% while maintains good absorbing performance. The results show that the model can optimize the absorbing performance and reduce the thickness to the maximum. The model established in this paper is suitable for many kinds of materials， not limited to the three kinds of materials， and can achieve the ideal optimization results.