The invention relates to a method for communication between an on-line operation system and an off-line simulation system in a power system and belongs to the field of automatic data processing of the power system. According to the method for communication between the on-line operation system and the off-line simulation system in the power system, a power system data transformation method based on transformation rule configuration is adopted, and the function of transformation of different formats and the function of distinction of the different formats are achieved according to difference between transformation rule files. Through generation of the transformation rule files for different data formats, a universal transformation rule analysis method is developed, a data transformation plug-in is reused, and transformation of the different data formats and data communication are achieved. The method for communication between the on-line operation system and the off-line simulation system in the power system has the advantages that the defects of existing manual maintenance, one-to-one transformation and a communication program are overcome, automatic transformation and communication of the data files of different formats are achieved, and the universality and the flexibility of transformation operation and communication operation are improved.