The invention discloses a purification assistant for coal chemical industry production and application of the purification assistant in the coal chemical industry production. The purification assistant for the coal chemical industry production comprises the following components in parts by weight: 90-99 parts of ethoxylated oleamine and 1-5 parts of fatty amine. The purification assistant has the beneficial effects that (1) the content of suspended solids in ammonium hydroxide and phenol are greatly reduced, therefore the separation effects of coal tar and coal cinder in the ammonium hydroxide and phenol are preferable, consequently, the loss of the coal tar is reduced and the yield of the coal tar is increased; (2) the water content in the coal tar is reduced; (3) a great number of sediments such as oil slag in each tank body and an evaporator tank heat-exchanging system are cleaned, the blockage phenomenon is avoided, the system cleaning frequency is reduced, and the service life of equipment is prolonged; and (4) the COD (chemical oxygen demand) and phenol content in gasification wastewater are reduced, and raw coke oven gas is cleaned at the same time. Therefore, the purification assistant provided by the invention is a high-efficiency product capable of reducing viscosity of coal tar and reducing water content of an oil product.