Stress jump coefficient at the interface between a porous layer and liquid was investigated for a configuration with natural flow parallel to the interface. An heterogeneous continuously varying interfacial layer between two outer buld regions was introduced. One-domain model in mesoscopic and two-domain model in macroscopic scale were founded respectively. The stress jump coefficient at the interface in two-domain model was determined by comparing with one-domain model based on given permeability and porosity profiles in the intefacial region in mesoscopic scale. The results showed that positive stress jump coefficient would be obtained when the interfacial region was located in the...