The invention provides a method and apparatus for lightweight data transmission between a substation and a master station. A transformer substation data model is described by adopting CIM/E; a transformer substation data model description file is generated; the transformer substation data model description file is converted into an interface file of the transformer substation data model; and finally transmission of the data between the transformer substation and the master station is realized according to the interface file of the transformer substation data model. According to the technical scheme, the transformer substation data model is generated based on the CIM/E; bidirectional association indexing of the transformer substation data model and a data exchange model is supported; the transformer substation data model only contains an entity object; the CIM/E adopts a flat structure, so that the size of the transformer substation data model description file is reduced; and in the process of transmitting the data between the transformer substation and the master station based on the interface file of the transformer substation data model, the transmission byte number is reduced by about 30%-90% in comparison with that in direct transmission of a structured text, the demand of the transmission of the data between the transformer substation and the master station on the communication bandwidth is reduced, and the lightweight transmission is realized.