Abstract: Gaoqian-3 area of Jinglou oilfield has entered the later stage of steam stimulation development and the steam stimulation effect became poor.In order to improve the development status,the nitrogen-assisted chemical viscosity reducing technology has been proposed to be adopted.Through models establishment,the simulation optimization on the injected volume of nitrogen and viscosity reducer,on the injection pattern,injection speed and injection time have been carried out.The results show the nitrogen-assisted chemical viscosity reducing technology is good and it can effectively improve the development effect and obviously increase oil.