Abstract: A contamination control plan was introduced to improve the cleanliness of slab amplifiers for Shenguang-Ⅲ laser driver, including laser structure optimization and precision cleaning methods, and the non-volatile-residue amount on the surface of mechanical structures was lower than 1 mg/m2 after precision cleaning. The illuminating cleaning experiment by flashlamp light was introduced to further improve the facilitys cleanliness. The results indicate that the cleanliness of Shenguang-Ⅲ laser driver is close to that of NIF, but better than other similar devices in the world. The aerosol concentration in Shenguang-Ⅲ amplifier cavity-during-flashlamp shots maintained among 5 000 to 10 000 particles (larger than 0.5 m) per cubic foot, and most of the surface organic residue was released at the first few shots and a clean amplifier was obtained finally. The significant improvements in cleanliness have provided a strong guarantee for the safe operation of Shenguang-Ⅲ laser driver.