Abstract: Presents a layered design scheme of embedded software for air conditioning. According to the characteristics of air conditioning software and the design idea of state machine, this software is divided into task scheduling layer, function logic layer, component driver layer and hardware configuration layer. The rule is: the upper layer can only call the function of its lower layer, and the lower layer can’t call the function of its upper layer. Data is transmitted between the layers by the interface. When one layer needs to be modified, the logic of the other layers is not affected as long as the interface is unchanged.

Key words: Embedded Software, Architecture Design, State Machine