Abstract: In-situ char and ex-situ char gasification characteristic was studied by using a newly developed micro fluidized bed reaction analyzer (MFBRA) and the reaction kinetics parameters were obtained. The in-situ char gasification proceeds using the same atmosphere, temperature and reactor in the gasification following the pyrolysis; the ex-situ char 1 gasification is defined as coal pyrolysis in Ar atmosphere and then gasification at hot state in the same reactor; and ex-situ char 2 gasification reaction is defined as coal pyrolysis in Ar atmosphere and then gasification after thermal annealing. By analyzing the three kinds of char, it can be seen that in-situ char has the largest specific surface area, lowest graphitization degree, and strongest sorption ability for CO₂. Under the minimized limitations of heat and mass transfer, in-situ char gasification has the highest reaction rate, and lowest reaction energy. The study also proves the reliability of MFBRA for in-situ char gasification reaction.