The comprehensive utilization of the coal-derived mineral resources is faced with technical difficulties. In the present work, the associated diatomite with high organic matter and high iron content in Xianfeng lignite was utilized for removal of TNT in Fenton system. The diatomite after purification was subjected to calcination at high temperature for the formation of ternary composite materials of diatomite-amorphous carbon-iron with N₂ as protective atmosphere. The influence factors such as processing conditions of diatomite, reaction time, H₂O₂ concentration, amount of diatomite and pH values for removal efficiency of TNT were investigated. The optimized technological conditions for adsorption and degradation of 50 mg/L with removal rate of 98% are 2 g/L ternary composite diatomite, 4 mL/L(30%) H₂O₂, 1 pH and 2.5 h of reaction time.