Planar flow casting (PFC) is an advanced technology to produce amorphous and nanocrystalline ribbons in electrical application. One of the major challenges of this technology is not only to have a rapid cooling rate to suppress the crystallization but also to achieve a high surface quality of ribbons. A new way to predict the fluid flow fields and heat transfer coefficient distribution of two types of single-roll cooling structures which are widely used in industrial production was proposed, i. e. 3-D time-independent steady simulation models. The flow velocity distribution of the two types of structures was calculated by software FLUENT, combined with energy and momentum equations. Additionally, the convective heat transfer coefficient distribution of the two structures was predicated. The results show that the velocity distribution of the roller with a water channel structure (WCS) is neither uniform nor periodic, and that of the roller with a water gap structure (WGS) is not uniform but periodic. The convective heat transfer coefficient distribution of the two kinds of rollers is not centrally symmetric, and the cooling feature of WGS roller is more regular. Three appropriate zones with symmetric distribution were predicated for a WGS roller, which was verified by the succeeding times of continuous production of ribbons. According to the thermal equilibrium principle, the heat transfer process of PFC technology was also described. These data suggest that uniform distribution of convective heat transfer coefficient can be one of the criterions to design the structure of cooling roller.