Abstract: The offshore wind turbine generators（DFIG） are difficult to maintain caused by their low accessibility, so the accuracy of fault identification is higher than onshore DFIGs.The slip power makes the fault characteristics very weak and difficult to identify when DFIGs are close to synchronous speed operation. An identification method was proposed for early faults of inter-turn short-circuit in rotor windings of offshore DFIGs, which was characterized by the differential value of（two-side linkage’s observation,TSLO）. According to the mechanism of the short-circuit fault in the DFIG rotor windings, the expression of the differential value of TSLO in the inter-turn short circuit was derived. Then the robustness of the fault feature to the slip variation and the rotational speed measurement error is verified by simulation. The simulation and experimental results show that the differential value of TSLO has high sensitivity and high reliability for the early fault identification of the rotor windings in DFIGs, which provides technical support for the accurate identification of the inter-turn short circuit of the rotor windings in DFIGs.