The invention discloses a power system capable of realizing online battery detection, which comprises a battery pack, a monitoring module, a rectifier module and a rectifying/inverting bidirectional module, wherein the battery pack is connected with a load through a test switch; the monitoring module is used for controlling the battery pack for battery detection; one end of the rectifier module isconnected with the mains supply and the other end is connected with the load for rectifying the inputted mains supply and providing power for the load and charging the battery pack in normal work; and one end of the rectifying/inverting bidirectional module is connected with the mains supply and the other end is connected with the battery pack for providing power for the load and charging the battery pack in a rectifying mode in normal work, and working in an inverting mode in the case of battery test to output battery discharging current. Online battery pack test for the power system can berealized, the test process is reliable and environmental friendly, and maintenance on the full network power supply system can be realized.