Solidification process and phase transformation behavior of DZ22B superalloys were analyzed by dif- ferential scanning calorimetry methods. After comparison of solidification microstructure with different cooling rates, the transition regularity of secondary dendrite spacing and carbidesphase were explored. Obvious dendrite refinement occurred with the increase of cooling rate, and the average secondary dendrite spacing decreased from 125 μm at the cooling rate of 5 K/min to 37 μm at the cooling rate of 80 K/min. The refinement of dendrite morphology was advantageous for the reduction of solute micro-segregation at later solidification stage, which generated the morphology change of carbides from continuous net shape to dispersive strips or blocks. Moreover, the skin effect of Hf element can be suppressed for higher cooling rate because of the thinner flowing channel and shorter solidification period, which can facilitate the formation of rich-Hf carbides.