Abstract: One of the effective approaches to simulating laminar-turbulent transitionflows is the transition\,\,/ turbulence modeling based on Reynolds-averagedNavier-Stokes equations. In this paper, its development is reviewed. First, we analyze the limitations of the so calledlow-Reynolds number turbulence models for transitional flows.These models, with modified damping functions for the viscous sublayer, seem to have some ability for transition prediction,while it is argued that it is just a chance coincident in numericalsimulation. Second, the correlation-based transitionmodels are discussed. These models, always constructed by considering theintermittency factor, take into account the physical mechanism of transitionin some extent, thus can model the transition procedure in several simpleflows. Unfortunately, it is not easy to make these models compatible with modernCFD methods because of the non-local variables in model equations. Thirdly,based completely on local variables, some recently proposed transitionmodels related to the new transport equations of laminar kinetic energy,transitional momentum thickness, Reynolds number and other characteristicparameters are analyzed. Finally, the future challenges are pointed out.