Abstract: In order to determine preferential steamflooding pathways formed during steam drive production in the heavy oil reservoirs in Block Qi40 of Liaohe depression, the parameters for geological evaluation of preferential pathways such as permeability, effective thickness, sedimentary microfacies, coefficient of variation and interlayer frequency are verified by using a combined method of static reservoir description and development performance analysis. Sandbodies of preferential pathways are determined and sample data are extracted on the basis of development performance characteristics. The weights of each parameter are determined by using grey correlation analysis method and fuzzy clustering analysis method is used to classify the steamflooding preferential pathways into 2 types and to obtain these parameters, based on which the standards of geological classification and evaluation are established for preferential steamflooding pathways and then fuzzy pattern recognition method is used to evaluate and predict the spatial distribution of the pathway. The practical application shows that this method is objective and accurate, which can provide basis for steamflooding development plan making