The invention belongs to an energy-saving and environment-friendly coal gasification solid waste treatment device and a treatment method. A coal gasification solid waste drying unit connected with a high-temperature tail gas supply unit is included, and tail gas of the coal gasification solid waste drying unit is connected with a tail gas emission chimney through a tail gas treatment unit. The high-temperature tail gas supply unit comprises a biomass combustion furnace with a combustor air blower. A combustion furnace body of the biomass combustion furnace is connected with a fuel bin througha fuel weighing belt conveyor. A tail gas outlet of the biomass combustion furnace is connected with a tail gas inlet in the side portion of a second-level three-return-trip drying machine feeding device through an air heating furnace. The coal gasification solid waste drying unit comprises a first-level single-barrel dryer and a second-level three-return-trip drying machine connected with a discharging port of the first-level single-barrel dryer. The tail gas treatment unit comprises a tail gas cooler, and a shell pass outlet of the tail gas cooler is connected with a static water mist dust remover. The advantages that the drying efficiency is high, the drying cost is low, the high-temperature tail gas can be effectively utilized for outer selling after coal gasification solid waste treatment, and tail gas white removing is achieved are achieved.