A longterm study was conducted to clarify effects of nitrogen application on yield and economic benefit of rice in the Liaohe River Delta,thereby providing a theoretical basis for the appropriate nitrogen application and nitrogen reduction.A 6year experiment,using cultivar Yanfeng 47,was conducted in Panshan county,Panjin city,Liaoning province from 2011 to 2016,and field trials included six N treatments:N 0，160，210，260，315，420 kg/hm2.The results showed that the reduction of rice yield,under excessive application of nitrogen fertilizer,was associated with deceases of the number of productive tiller and thousand grain weight and an increase of the percentage of undeveloped grain;the order of nitrogen recovery efficiency and agronomic efficiency was N160=N210>N260>N315>N420，and for partial factor productivity of nitrogen the order was N160>N210>N260>N315>N420.The nitrogen recovery efficiency and agronomic efficiency tended to increase with prolonged experimental time;optimal rates of nitrogen application with yield and economic benefit showed an increasing trend from 2011 to 2012,and then it tended to be stable since 2013.Hence,the nitrogen threshold in the Liaohe River Delta should be 210~245 kg/hm2,which significantly decreased nitrogen input by 5.77%～19.23% compared with local one.