Salvaging waste-heat from system’s kilns and boilers in Waste-Heat Recovery System (WHRS) for generating electricity is being a potential opportunity in Vietnam. This paper aims to build a model for simulating the WHRS of Holcim cement factory-Kien Giang. The model then will be implemented as an available scientific base for other factories in Vietnam. The existing WHRS of factory is simulated in order to demonstrate the accuracy of model so that the results can be used for modeling a new solution which salvages waste-heat from water-boiler of system. Results of the simulation are closely similar to parameters obtained from the existing system. The new suggestion of waste-heat salvaging shows impressive results with 34.5% increase of generator power and 33.3% raise of electricity energy in comparison with the existing system; 1.32 million USD is saved, and 10.3 tons of CO2 is mitigated annually by implementing the new WHRS one. For its positive results, the system then will be implemented commercially for other cement factories in Vietnam.