With the extensive applications of lithium ion batteries, many batteries fire and explosion accidents were reported. Base on the combustion triangle theory, the combustion triangle contributions of lithium ion battery were analyzed. By using C80 micro calorimeter, the thermal behavior studies on the materials show that the flammable electrolyte, oxygen generated by charged cathode and anode decomposition, and exothermic reaction heats form the combustion triangle together. The thermal runaway of working materials in lithium ion battery system was studied with common used battery materials, and the no return temperature TNR was calculated is 75oC and the self-accelerating decomposition temperature (SADT) is 66.5oC. Further analysis shows that the lithium ion battery reaction chain according with Domino effect, therefore, the lithium ion battery fire and explosion developing sequences was drawn by Domino chain. The Domino chain explains the fire and explosion developing process perfectively, and then the countermeasures can be taken by breaking the Domino chain for the safety of lithium ion battery.