The invention provides a method and a device for treating residual sludges. The method for treating residual sludge comprises the steps of mixing the residual sludges and conditioners evenly, placing the mixture in a ventilation location for 7-16 d, artificially stirring once every 12-36 h, after mixing the residual sludges and a conditioner for 7-16 d, adding earthworms to form compost, waiting for 56 - 63 d to obtain an earthworm fecal sludge product. The earthworm fecal sludge product is applied in high efficient fertilizers or soil conditioners. By adding cow dung as conditioners, the adverse effects of residual sludge on the earthworms are alleviated, and the growth and reproduction of earthworm in the compost are improved, the earthworm biomass balance is ensured, the organic matter degradation ability of earthworm in the compost is enhanced, thus the composting efficiency is improved. The method and device for treating residual sludges provide an effective way for the resource utilization of sludges in towns and villages.