Dendrite structure in solidification process has been studied by many researchers for it’s widely existence. In present work, a cellular automata model was proposed according to the basic physical chemistry concepts, which was helpful for a better understanding of the dendrite crystal growth and its physical chemistry mechanism. Two kinds of structures were considered in the model: hexagonal and rectangle. The status of every site was set as 0 and 1 which represent non-solidified and solidified state. Temperature field was simulated using finite difference method on the same mesh. The states of sites were changed according to the overcooling condition only. The computer simulation results showed that dendrite structure could be obtained under overcooling condition and temperature field calculation only, the structure of the dendrite was decided by the geometry of the model. The simulation resulted similar pattern as that obtained by experimental observation. The present model suggested that there exist a very simple basic for the typical complex phenomena, dendrite structure.