The formation of the microstructure and the evolution process from dendrite into equiaxed structure during atomized process for spray formed superalloy were analyzed. The results showed that the characteristic non dendritic equiaxed structures during deposition for spray formed materials were formed resultantly due to the fact that nuclei multiplication caused by dendrite fragmentation and remelting in semi liquid layer acted as effective nucleation sites for the formation of equiaxed structure in combination with the coalescing and coarsening of dendritic arm fragment as well as the homogenizing and coarsening of slightly deformed solid dendrite.