Thermal recovery of the 4×2×3 multi-segment amplifiers that will be used for SGIII laser facility was presented. A lumped mass model was used to investigate the thermal recovery processes of the flash lamps, blast shield, and laser slab. A 3-D finite element model was used to investigate in detail the time related spatial temperature distribution of the laser slab. The preliminary calculating results indicate that, with an optimization thermal recovery, we can reduce the thermal gradient and the average temperature of the slab to an acceptable value.