1. A method for showing hierarchical structure for a given power intent described in a power intent description language with a design described in a hardware design description language, the method comprising the steps of: retrieving, by utilizing a processing circuit of an electronic device, hardware design description contents written in the hardware design description language from a hardware design description file, and retrieving, by utilizing the processing circuit, power intent description contents written in the power intent description language from a power intent description file; creating, by utilizing the processing circuit, a data structure of a power domain hierarchy according to the power intent description contents and the hardware design description contents respectively retrieved from the power intent description file and the hardware design description file; creating, by utilizing the processing circuit, the power domain hierarchy for coverage annotation, debugging, or design review according to the data structure of the power domain hierarchy; and controlling, by utilizing the processing circuit, a display module to display the power domain hierarchy associated with the power intent description contents and the hardware design description contents respectively retrieved from the power intent description file and the hardware design description file, wherein the power domain hierarchy comprises at least one power domain.