A diaphragm wall down-the-hole hammer trenching machine comprises a crane, a guide frame, a push-pull device, cluster down-the-hole hammers, gas collecting hoods, a high-pressure medium pipe or cable, and a slurry discharge pipe. The crane suspends the guide frame; the cluster down-the-hole hammers are connected to the bottom of the guide frame by means of the push-pull device; each cluster down-the-hole hammer comprises a primary hammer and secondary hammers; the plurality of secondary hammers are provided on each primary hammer; one gas collecting hood is provided on the lower part of each primary hammer; the high-pressure medium pipe or cable passes through the guide frame and the push-pull device to enter a primary hammer distribution pipeline to drive the secondary hammers to perform percussive drilling; mud channels are provided in each primary hammer; and the slurry discharge pipe passes through the guide frame and communicates with the gas collecting hoods.