Mild pyrolysis is one of the precombustion mercury control techniques. Mercury removal efficiency through mild pyrolysis has close relation with the weak thermal stability of mercury in coal. The thermal stability mercury in coal has been identified by solvent extraction procedures combined with temperature-programmed decomposition techniques. The result shows that the carbonate-bound mercury, iron-manganese oxide-bound mercury, organic-bound mercury, and sulfide-bound mercury should be classified into the weak thermal stability mercury and can be removed by mild pyrolysis. Therefore, a method can be established to evaluate the mercury removal ability by determining the carbonate-bound mercury, iron-manganese oxide-bound mercury, organic-bound mercury, and sulfide-bound mercury through solvent extraction procedures. This result of this method is in good agreement with the result of heat treatment experiment, indicating that this method is an effective approach to evaluate the mercury removal efficiency through mild pyrolysis.