在实验分析的基础上,建立了反映颗粒流体系统非线性特征的数学模型,定性地描述了颗粒流体系统的历经性及其各种流动状态中的主要非线性特征,从而说明了颗粒流体系统是具有混沌、耗散、有序与无序等复杂特征的非线性系统.“,”At the Institute of Chemical Metallurgy, considerable experiments have been carried out for particle fluid system. These experiments showed the chaotic behavior in particle fluid system. We, using Logistic model and linear transform, succeeded in establishing a descriptive model for formulating the nonlinear chaotic change and nonlinear period doubling phenomenon of this system. Our nonlinear model is mathematically formulated with eq.(1), in which ε n and ε n+1 are both instantaneous voidages. Eq.(1) can describe the experimental characteristics that ε becomes more and more scattered in the fluidization regime with increasing gas velocity and that ε suddenly converges to a single value with the onset of choking. μ in eq.(1) is the controlling parameter. μ has a series of critical values, each of which corresponds to an inflective change of flow structure. In section 3, we discuss fully such inflective changes. Our discussion is in terms of λ , which is convenient for discussion and is mathematically related to μ through Logistic model. With our model it is possible to infer nonlinear characteristics of particle fluid system other than those already observed.