Solvent extraction of nitrogen compounds from catalytically-cracked diesel oil was studied by using 95% ethanol solution containing a small amount of metal ion. Catalytically-cracked diesel oil from Shengli crude oil was used as feed oil. Nitrogen compounds, especially basic nitrogen compounds, were effectively separated by solvent extraction based on chemical complexation. The stability of catalytically-cracked diesel oil was greatly improved. Experimental conditions for the separation of nitrogen compounds were investigated. The recovery of catalytically-cracked diesel oil was quite high, which shows promising potential for the new method.