Abstract: It lays a foundation for finding out the VOCs emission sources in the production process of synthetic ammonia industry and accounting the industrial emissions. In this paper,the emission characteristics of synthetic ammonia industrial in coal chemical industry were studied. The research included the organized emission in the production process,the workshop emission and the unorganized emission in the plant boundary. The emission was estimated by the emission factors. The results show that the aromatics and oxygen-containing organics are the main emissions of synthetic ammonia. 36,19,26,21 and 20 VOCs species are detected in the sulfur recovery process,urea synthesis process,CO_2 flash gas in low-temperature methanol washing process,the exhaust gas of CO_2 flash and washing tower,respectively.Benzyl chloride,isopropanol and 2-butanone are the characteristic pollutants of VOCs emission in synthetic ammonia. A large amount ofbenzyl chloride produced in the production process may be converted from aromatic compounds with α-hydrogen side bond. the unorgan-ized emission characteristics of synthetic ammonia workshop are consistent with the emission characteristics of the corresponding productionprocess. 19,32 and 15 VOCs species are detected in gasifier workshop,urea packaging workshop and phenol Ammonia Recovery Workshoprespectively. The VOCs discharged from the gasifier workshop are mainly benzyl chloride,accounting for 23.16%,the urea packaging work-shop is mainly 2-butanone,ethyl acetate,1,2,4-trimethylbenzene,accounting for 49.58%,the phenol ammonia recovery workshop ismainly vinyl acetate,accounting for 56.60%,which is related to the auxiliary solvent used in the process of phenol ammonia recovery. Thecharacteristics of VOCs at unorganized monitoring points in the plant boundary of synthetic ammonia are:aromatic hydrocarbon > halogena-ted hydrocarbon > oxygenated organic matter > alkane,which is consistent with the emission characteristics of production process corre-sponding to each monitoring point.The total emission factors of synthetic ammonia process calculated by emission factor method are 75.02 g/tsynthetic ammonia,13.66 g/t synthetic ammonia with sulfur recovery,14.45 g/t synthetic ammonia with urea synthesis,21.42 g/t syntheticammonia with CO_2 flash gas,13.01 g/t synthetic ammonia with CO_2 flash exhaust gas and 12.49 g/t synthetic ammonia with tail gas scrub-ber vent gas. According to this emission factor,the VOCs emission of a typical coal based synthetic ammonia production process in InnerMongolia was about 22.51 t in 2015.