This paper is devoted to the optimization of energy conservation operation in high-tech manufacturing factory. A method which employed here that would construct the operation model of a factory by using its operative data, and then find the optimized operating variables through the process of optimization calculation. A lot of references concerning the model reconstruction for the single type of the process equipments have been well-known. However, various types of equipments actually interact with each other in a high degree correction in a factory. For this reason, this paper dedicated to the optimized design of chiller water system including the chillers, cooling towers, cooling water pumps, ice water first side pumps, and ice water second side pumps.