In gas-solids flows and in dry granular flows che experimental determination of the effects of all influencing factors is rather tedious, time and cost consuming. Therefore, suitable models an simulation methods can help us to understand the various flow phenomena, to predict the flow characteristics and to determine the influence of the operation parameters and material properties. Generally, two main modelling philosophies can be distinguished. The first category of models do not consider the particles as individuals and the microstructure of the bulk solids is not examined, while the second category of models calculate the movements of the individual particles. Both modelling methods can be used effectively, bur the results obtained by any of then need validation by comparing them with real experimental results. This paper makes a survey of the main modelling methods and demonstrates some of the authors＇ own results obtained by stochastic simulation and DPS method.