Abstract: The effects of organic and biogas slurry fertilizer from pig manure of a large scale farm on paddy soil pH, Hg, Cd, Cr, Pb, Ni, As, Cu and Zn content and environment quality were studied based on data from a 4-year location test of different fertilization systems. The results showed that the application of organic and biogas slurry fertilizer regulated soil pH, the regulation effect of organic fertilizer on acid was better than that of biogas slurry fertilizer, and the regulate effect of high amount organic fertilizer on acid was better than that of medium amount organic fertilizer. The application of organic and biogas slurry fertilizer had no obvious effect on soil Cd, Cr, As, Hg, Pb and Ni content, but the accumulation of Cu and Zn was obvious. In terms of the influence on soil environment quality, the application of organic and biogas slurry fertilizer had more effect than that of chemical fertilizer, the pollution of Cu and Zn in soil could be caused by 4-year application of organic fertilizer with the application amount of 22500 kg/hm² per year. The pollution might be in an alert range when organic fertilizer application amount was 11250 kg/hm² or biogas slurry fertilizer application amount was 225 000~ 450000 kg/hm². The recommended application amount was organic fertilizer 11250 kg/hm² and biogas slurry fertilizer 450000 kg/hm², and consecutive application in the same field should be avoided.