Abstract: For the preparation of needle coke,thermal conversion of FCC slurry to mesophase pitch was carried out in a multi-tube,well-crucible with programmable temperature control,with the use of group component analysis for quantification,and optical microscope and()~1H-NMR to track the thermal conversion.Results show that three steps,i.e.mesophase micro-crystal formation,mesophase micro-crystal growth and mesophase spherule coalescence,are involved in the formation of mesophase.The first two steps are slow,while the last is fast.Experiments also reveal that the insoluble fraction increases at elevated temperatures.