The traditional construction mode of power dispatching automation systems at prefecture and county level are costly， inconvenient and inefficient. A new concept of integrated prefecture and county power dispatching automation system is introduced. Various modes such as remote workstation mode， distributed data acquisition mode， tightly coupled mode and mixed mode are introduced in detail. And the key technologies of each mode has been analyzed concretely. The important factors to choose different construction mode has been given by comparing each mode and analyzing application conditions.