Abstract: Time series modeling is more difficult but more meaningful than the modeling on the average characteristics of the system.It has recently been shown that the fluctuation behavior in the system with vapor-liquid-solid boiling flow is chaotic.Hence, the time series modeling was studied in this work from the point of view of nonlinear hydrodynamics.Based on the time series data of wall temperature of heated tube in an evaporator with vapor-liquid-solid boiling flow, the genetic algorithm is used to develop global models by which the nonlinear hydrodynamic behavior of the system can be described in different operation conditions.The model equations were in the forms of iteration functions.Comparison and analysis of the data obtained from the model and those from the experiments were made.The results showed that the calculated values from the models were in good agreement with those measured in the experiments, and the hydrodynamic behavior of the vapor-liquid-solid three-phase flow system can be well described by these models.