The invention provides a desulfuration and ammonia distillation device for coal gas purification, and relates to the technical field of auxiliary equipment for coal gas purification process. An ammonia distilling tower (9) of the desulfuration and ammonia distillation device for the coal gas purification is communicated with an ammonia washing tower (11) through a pipeline I (10), the pipeline I (10) is communicated with a crude benzene separation water tank (5) through a pipeline II (17), and an underground pump (14) is arranged between the crude benzene separation water tank (5) and the pipeline II (17). The desulfuration and ammonia distillation device for the coal gas purification according to the invention has a simple structure, crude benzene separation water in the crude benzene separation water tank of the desulfuration and ammonia distillation device for the coal gas purification can be quickly pumped into the ammonia washing tower, and the crude benzene separation water produced in the operation process of the desulfuration and ammonia distillation device for the coal gas purification is used to replace ammonia distilling water for operation in an alkaline washing segment of the ammonia washing tower, so that the consumption of the ammonia distilling water as alkaline liquid diluting water is reduced effectively, operation load of a solvent dephenolization and ammonia distillation system is reduced, ammonia distilling steam consumption is lowered, and wastewater treatment cost is reduced.