The invention relates to a program automatic configuration method of sub-modules in an intelligent power device. The method of the invention comprises the steps as follows: when a module is powered for the first time, performing ID setting to each module, and extracting a program and a configuration file of an adjacent sub-module via a configuration unit integrated in the sub-module and storing the program and the configuration file in the configuration unit according to the ID information of the module; when the sub-module is replaced, finishing the ID setting to the sub-module with the adjacent modules, and performing backup to the sub-module according to the ID information with the adjacent modules and finishing the automatic configuration of the sub-module via a network. The method of the invention performs automatic configuration to the sub-modules via the configuration units integrated in the sub-modules and does not need to add extra modules and could recover the module program automatically. The synchronization of the information in the configuration units of the adjacent sub-modules enables any adjacent modules to update the configuration when the sub-module is replaced. The method of the invention is especially suitable for a randomly expended structure and a plug and play external connecting mode of the intelligent power device with multiple processing units.