Abstract: Reduced crude in Shengli oilfield contain not only Ni and V but also large amount of Na. Conventional metal deactivator can inhibit contamination of Ni and V to catalytic cracking catalysts, however, it has no effects on toxicity of Na to catalysts. DNDVN1 is a water soluble metal deactivator that can deactivate Ni, V and Na. Industrial application of DNDVN1 in the 600kt/a heavy oil catalytic cracking unit in Shengli Petrochemical Plant shows that it can lower product recovery rate of dry gas and coke 2.39% and 9.7% respectively in comparison with that of the conventional deactivators. Yields of gasoline, liquefied gas and light oil insrease 2%, 0.7% and 1.24% respectively.