Abstract: The critical operation technology for controlling shot coke formation in the delayed coker has been established in SINOPEC Luoyang Company. Based on the mechanism of shot coke and tests results, it is pointed out that the critical operation conditions, under which the shot coke will be occurred, can be strictly controlled by reducing recycle ratio and reaction pressure and increasing the reaction temperature to obtain the highest liquid yield. Meanwhile several measures, including monitoring neutron level indicator of point C on the coke drums, amount of quench, temperature of point C on coke drums, and optimal coker operation conditions, have been adopted to build a forecasting system for the shot coke formation, which would provide security and operational basis.