Abstract: To overcome the difficulties and drawbacks in modeling the dynamic systems by using traditional methods, a hybrid evolutionary modeling algorithm （HEMA） is proposed to model the dynamic system with a system of ordinary differential equations （ODEs） whose main idea is to embed genetic algorithm （GA） in genetic programming （GP） where GP is employed to optimize the structure of a model, and GA is employed to optimize the parameters of a model. It has succeeded in automating the modeling process of systems of ODEs for dynamic systems. The computational experiments indicate that, by running the HEMA, the computer can search out multiple superior ODEs models in a reasonable time. Compared with most available modeling methods, such as the grey systems method （GSM）, this algorithm possesses the advantages of automation of the modeling process, more flexible and various model structures, wider range of applications, and higher precision of fitting and predicting data.