RZ-SHAW is a new developed model coupling the Root Zone Water Quality Model (RZWQM) and the Simultaneous Heat and Water (SHAW) model. The objective of this study was to evaluate RZ-SHAW (RZWQM-SHAW) for simulations of soil water and soil temperature of Siberian Wildrye grassland in winter by comparing with the SHAW model. Soil parameters, residue data, and data of total soil water content, liquid water content and soil temperature data of four soil layers were measured in the irrigated experiment of siberian wildrye (Elymus sibiricus L.) in semi-arid Agropastoral Ecotone of North China during 2005 to 2007. Hourly weather data were collected from Guyuan weather station. The results showed that RZ-SHAW model provided similar goodness-of -prediction statistics as the original SHAW model for simulated total soil water content, liquid water content, and soil temperature. This successful coupling of RZWQM and SHAW has a potential application for simulating and predicting of crop growth, crop water use, and sustainable water management in terms of the whole year or continuous several years.