Abstract: SINOPEC have required all its subordiante oilrefining and chemical engineering enterprises to stop leaded gasoline production and start unleaded gasolincproduction betore July,1, 1999. It is practical to produce90 unleaded gasoline in Henan Oilfield Refinery throughtechnical innovations such as controlling carbon residue ofraw materials within 1 .8 - 3.0%, replacing lanthanon hydrogen type- Y catalyst with modified compoundultra -stable type - Y catalyst to increase RON of gasolineand improving operating conditions.