Presents the optimization goal for minimizing the sum of first cost and operational cost of a cold air distribution system with ice thermal storage, establishes the mathematics model which couples design optimization and operational optimization, puts forward a calculation method and develops a computer program for the system optimization. Completes a case's study which is about the optimization issue for the cold air distribution system with ice thermal storage in an office building in Xi'an, analyses the impact of two key parameters: ice storage factor (the ratio of ice storage capacity for air conditioning to cooling load of the design day) and supply air temperature on system optimization, determines optimized ice storage factor and supply air temperature, finally carries out the economical analysis on the system life cycle costs comparing with a traditional air conditioning system.