The utility model discloses a direct current islanding operation stability closed loop simulation detection device which comprises a power station monitoring device, an excitation control device, a governor electrical adjusting device, a governor actuator, an extra-high-voltage direct current control and protection device, a real-time simulation device, an interface interaction device and a power amplifier. The power station monitoring device, the excitation control device and the governor electrical adjusting device acquire the control observed quantity of the real-time simulation device through the interface interaction device and the power amplifier, and inputs control information into the real-time simulation device. The extra-high-voltage direct current control and protection device carry out direct current transmission system control operation. According to the utility model, the frequency stability, the voltage stability and the machine network coordination control characteristic of a large capacity direct current islanding system are detected; the period of a field test is shortened; risks of the field test are evaded; the safety and the stability of the operation of a power system are improved; and the direct current islanding operation stability closed loop simulation detection device has the advantages of flexible operation control, high simulation result precision and the like.