The invention discloses a compound uncoupling agent which is used for deweighting treatment of residual sludge in the sewage treatment technology with the activated sludge process. The compound uncoupling agent comprises 3,3,4,5-tetrachlorosalicylamide, refined diatomite and zeolite. When one part by weight of 3,3,4,5-tetrachlorosalicylamide is provided, 0.05-1.0 part by weight of refined diatomite is provided, and 0.05-1.0 part by weight of zeolite is provided. The compound uncoupling agent provided by the invention can obviously lower attenuation on sludge activity while keeping favorable sludge decrement performance and has obvious active effect, which embodies on the aspect that the sludge decrement performance is enhanced, for example, the added TCS can be reduced by 20-60% for reaching the same sludge decrement ratio; after TCS is added in a system, COD strainaway rate is not affected on the whole.