Sufficient water storage in root zone during winter time not only benefits crop growth in next spring,but also potentially increases the yield. Water movement in root zone was often simulated by using the coupled water and heat transport(CWHT) model during soil freezing-thawing process and influenced by multiple factors such as boundary conditions,parameters determination method,and so on. An improved method based on in-situ measured data was proposed to optimally estimate the parameters in the CWHT model. ...