Traditional methods are difficult for the purification of TATB due to its poor solubility. Green deep eutectic solvent （CS-1） displays good solubility toward TATB， so CS-1 was used as the solvent with water as back extractant to develop a new purification method for TATB in this study. The difference between this method and other methods were investigated for the purification of TATB. Purification conditions including the amount of back extractant， washing times and drying methods were comprehensively optimized to improve the purity of TATB. Finally， a new method has been established for highly efficient separation and green purification of TATB. Through this method， high-purity TATB was obtained with the purity of （99.7±0.2）% and good recovery of 92.5%. Further， spectroscopic monitoring was combined with theoretical simulation to study the kinetics of the purification of TATB， and then a purification mechanism has been proposed， which is based on the dissociation of TATB’s complexes through the competition of hydrogen bonding between CS-1 and water.