System and method applied to monitoring direct-current power of a photovoltaic generation module

A monitoring system and method is applied to monitoring a direct-current (DC) power of each of the photovoltaic generation modules in a solar power system. The monitoring system includes an electric power capture unit such as an electromagnetic sensing element, a current diverter or a resistance, which is assembled at outside of each of the photovoltaic generation modules for capturing a direct-current power to generate an analog voltage signal. The analog voltage signal is converted into a direct-current digital signal by an analog to digital conversion apparatus. Then the direct-current digital signal is transmitted to a firmware through a wired or wireless communication module. The firmware determines whether the DC power of each of the photovoltaic generation modules meets a standard value or not according to the received direct-current digital signal, and converts the direct-current digital signal into a text information for displaying on a display unit.