A kind of fault detection oscilloscope device and method for the quality of power and the electrical system are disclosed, which belongs to the field of detection technique of electric system, and it includes three subsystems: detection oscilloscope subsystem, remote-control monitor subsystem, and time setting subsystem; the oscilloscope subsystem can do multi-point diagnosis for electric system, and detects and records the quality parameters of power; the remote-control monitor subsystem consists of precedence sever and Internet client, and it can realize the double action that transmitting fault information and monitoring the daily running of protective and safe device; the time setting subsystem provides the system time and insures the time synchronization with system; the realizing method includes dynamic parameter measurement, fault time division; starting criterion, fault oscilloscope, uploading record, and remote-control command procession. The invention realizes the digitalization, network, intelligent, and integration of detection oscilloscope device, and it can improve the quality of power, ensure the equipment running safely and steadily.