Various approaches have been proposed to model particle-fluid flows at different time and length scales, including, for example, the so-called two-fluid model (TFM), direct numerical simulation (DNS) and combined continuum and discrete model (CCDM). This presentation briefly discusses the key features and relative merit of these models. Focus is then given to CCDM in which the motion of individual particles is obtained by solving Newton’s second law of motion and fluid flow by the Navier-Stokes equation based on the concept of local average. In recent years, this approach has been rapidly developed worldwide, mainly as a result of the rapid development of discrete particle simulation technique and computer technology. This talk will present an overview of the work in this direction in my laboratory SIMPAS at the University of New South Wales. First, the multiscale nature of particulate research will be briefly introduced. Then, the coupling between approaches at different time and length scales ranging from sub-particle, particle, local averaged computational cell to process equipment scale will be discussed. The discussion is then extended to the coupling between discrete particle flow and continuum fluid flow, and the link between fluid flow and heat transfer. Emphasis will be given to the recent developments and application in the modeling of complex particle-fluid systems such as three-dimensional fluidization and heat transfer, pneumatic conveying, gas and dense medium cyclones, and industrial applications. The examples will demonstrate that CCDM approach has gradually emerged to be a useful tool not only for fundamental research but also for engineering application. Finally, areas for future development are briefly discussed.