Based on the monitoring data, a practical information management system of safety assessment and warning for Nuozhadu earth-rockfill dam is developed. The system includes system management module, safety criteria module, monitoring data and engineering information module, numerical calculation module, back-analysis module, safety warning and contingency plan module, and data base and management module. The numerical calculation and back-analysis modules are the key parts, which perform analysis of seepage, stress and deformation of dam, crack of dam, dynamic response and slope stability. The parameters of constitutive model are back-analyzed by using the monitoring data and the behaviors of the dam at some important time are predicted.