With the principle of dynamic description logic, which introduces the concept of grid domain ontologys knowledge representation, a system is built that can be shared by each businesses ontology knowledge base in smart grid. First, combine attributive concept language with complements language using dynamic description logic with ALC language to build a smart grid domain ontology. And then use the ontology knowledge to build the final ontology knowledge base that can greatly improve the efficiency of information query and clearly express the basic concepts, properties, processing methods and internal relations of the smart grid domain knowledge, which is conducive to promote China's smart grid construction.