Direct coal liquefaction process using inferior oil

The invention discloses a direct coal liquefaction process using inferior oil. The process comprises the following steps: carrying out purification treatment on inferior oil, carrying out vacuum distillation or atmospheric distillation on the inferior oil subjected to purification treatment, and cutting the factions into light oil fractions at a temperature lower than 230 DEG C and heavy oil fractions at a temperature higher than 230 DEG C; subjecting a coal oil mixture obtained by mixing pulverized coal with the heavy oil fractions at a temperature higher than 230 DEG C, hydrogen and a catalyst to reaction in a primary reactor at a reaction temperature of 420-460 DEG C, sending a primary reaction product to the upper part of a secondary reactor, enabling a gas phase component in the primary reaction product to flow out from the top of the secondary reactor, enabling solid and liquid components in the primary reaction product to flow down in the secondary reactor to carry out countercurrent contact reaction with hydrogen flowing up at a reaction temperature of 430-480 DEG C, and carrying out fractional distillation after the reaction ends. The process has the effects of obviously improving the production efficiency of direct coal liquefaction and improving the quality of naphtha and diesel products, and is suitable for the large-scale direct coal liquefaction industry.