The invention discloses a method for treating sludge by composite thermophilic bacteria. Firstly, bio-enzyme catalysts accounting for 0.05 mass percent of the total mass of the sludge and industrial hydrogen peroxide accounting for 10 mass percent of the total mass of the sludge are added; a subcritical microbubble processor is used for performing cyclic treatment for 15 minutes on the sludge; thesludge is pumped into a sludge press filtering dewatering machine to be dewatered until the moisture content reaches a value below 50 percent; the sludge filter cake is formed; the sludge filter cakeis crushed by a crushing machine to obtain sludge particles with the particle diameter being smaller than 5mm; the composite thermophilic bacteria are sprayed onto the sludge particles; mixing and stirring are performed; 3 to 8 weight percent of edible fungi, 2 to 6 weight percent of fragrant eupatorium herb powder, 3 to 6 weight percent of tobacco stem residue, 6 to 10 weight percent of fly ashand 0.5 to 1 weight percent of lanthanide oxides through being metered in percentage by weight in the total weight of the sludge are added; after the sufficient and uniform stirring, the heat insulation fermentation is performed. The method has the advantages that the flow process is simple and convenient; the efficiency is high; the sludge quantity can be fast reduced; the heavy metal can be passivated; the harmless and resource treatment of the sludge can be thoroughly realized.