Abstract: For the reason of the unstable evaporation in the tar sampling process and the difficulty of measuring and controlling reaction temperature, a moving bed as the tar sample introduction system was designed. A sample tray carrying tar was moved into the furnace with linear temperature distribution of the entrance zone. The movement of the tray instead of that of the tar, makes the tar sample introduction process more stable and the temperature easer to control. On this basis, tar cracking process and kinetic characteristics with the different sample introduction rate were studied. The results indicate the tar cracking rate is accelerated with increasing temperature at 573~1 123 K. The tar cracking rate reaches 58% at 1 123 K. The tar thermal cracking reaction is a first order reaction. On average, the activation energy is 39.5 kJ/mol and the pre-exponential factor is 1.58 min^-1.