Abstract: The paper studied many complex large system modeling method, and analysed their advantages and disadvantages. Furtherly, its research purposes were put forward, and it is a new complex large system modeling method suitable for China's administrative hierarchy mechanism, and is able to effectively solve uncertainty of system information, especially coexistence of fuzziness and randomness. According to the research target, the paper discussed multi-layer state space model, described specification of its latitude model, and combined with the principle of the normal cloud generator,proposesd a "decomposition-collection" type of uncertainty intelligence modeling method: multi-layer cloud modeling method. Finally, it was used to analyse China's energy system, and got a active result, which shows the method is simple and effective.

Key words: Multi-layer state space model, Cloud model, Uncertainty, Complex large system