Disclosed are a device for strengthening anaerobic sludge digestion based on conical-coiled pipe coupling and an anaerobic sludge digestion method. The device comprises a feeder (A-3, B-3), a conical-coiled pipe coupling reactor (A-1, B-1) and a thermostat (A-4, B-4), wherein the bottom of the feeder (A-3, B-3) communicates with the top of the conical-coiled pipe coupling reactor (A-1, B-1), and the bottom of the feeder (A-3, B-3) is flush with the top of the thermostat (A-4, B-4); the conical-coiled pipe coupling reactor (A-1, B-1) is arranged in the thermostat (A-4, B-4); the whole coupling reactor (A-1, B-1) is in a regular cone shape or an inverted cone shape; and a main body of the coupling reactor (A-1, B-1) is a coiled pipe (A-2, B-2).