The invention provides a novel process for removing ashes from a synthetic gas and recovering washing heat. The process comprises the following steps: performing oxygen deficiency gasification reaction on coal powder and an oxidant in a combustion chamber of a gasifier; introducing a crude synthetic gas into a flue gas cooler and a waste heat recovery system to perform preliminary cooling and recover a heat byproduct of steam; removing dust from the cooled crude synthetic gas by virtue of a cyclone separator and a bag-type dust collector; and collecting and continuously discharging fly ashes by using an ash bin and an ash pump which are arranged at the bottom of equipment. According to the process, gasification circulating flushing water is adopted as washing water of a washing tower and slag flushing water at the bottom of the gasifier, and is recycled after pretreatment, and ash residues are continuously discharged by virtue of a slag dragging machine. By adopting the process provided by the invention, the purification effect of the crude synthetic gas can be improved, the sewage discharge can be reduced, and the process flow and equipment are simple.