Abstract: After the transformation of FCC gasoline hydrogenation unit according to national standard of grade Ⅴ gasoline, some problems of the splitter of selective hydrogenation unit arose, such as low separation accuracy, low reflux ratio, low automatic control rate of the control loop and control lag of on-line sulfur analyzer for light gasoline(LCN). Through analyzing the reasons, it was proposed to change the on-line sulfur configuration control of LCN, re-adjust PID parameters of control loop, and optimize the splitter process parameters, and so on. After above measures were carried out, the temperature difference between 10% range of HCN and 90% range of LCN increased to over 40 ℃, the segmentation precision of splitter improved, and the LCN withdrawal ratio increased by 3 percentage points. The FBP of LCN was 65-67 ℃, which could meet the requirements of etherification unit. The top pressure of splitter decreased from 0.89 MPa to 0.81 MPa. In the case of same processing capacity, the outlet temperature of splitter reboiler furnace reduced 8-10 ℃, and the fuel gas consumption of the reboiler furnace reduced 190 m³/h. The economic benefit was notable.