It's disclosed a current monitor and an electric power quality compensation system. The current monitor includes: an internal monitor module configured to output a measurement of current for characterizing a real-time electric power quality of an external power network based on a received detection current, wherein an external detection module is used to detect a current of the external power network and output a first level detection current; and an isolation and transfer module including an input side and an output side electrically isolated from each other, wherein the input side is configured to be connected with the external detection module, and the output side is configured to be connected with the internal monitor module, the isolation and transfer module receives the first level detection current and outputs a second level detection current to the internal monitor module.