Alkylation of coker diesel produced by PetroChina Fushun Petrochemical Company No. 1 Refinery was investigated in this article. Complex of aluminum trichloride and trichloromethane was used as a catalyst. Ejects of catalyst amount, reaction temperature, and time on the distribution and quality of the product were studied. The results showed that when the reaction temperature was 60 C, ratio of benzene to alkene was 8:1, reactive time was 6 It, the ratio of catalyst quantity in the reactive liquid was 5% (wt), and yield of heavy alky benzene could reach 19.6%. The quality of coker diesel had been significantly improved through this method.