Abstract: By analysis of the operation data it is found that the asphaltene and salt content are the main factors influencing the heating furnace operation period for our coking unit and that once the asphalt content is more than 18% and the salt content is higher than 10 mgNaCl/L, the operation cycle of the heating furnace is sharply shorten, the shortest one is about 2 months. By strengthening raw material control, establishing early warning value, timely adjusting circulation ratio and reaction temperature as well as adjusting the gas injection rate, the cycle can be extended to 4 months. The operation practice proves that as long as the asphalt content is not greater than 18% with the salt content less than 10 mg NaCl/L, the heating furnace operation cycle can be prolonged to 5 ~ 6 months.