Abstract: In the current situation of implementing the dual-carbon goals, offshore wind power is gradually emerging as a new option for the green and low-carbon energy supply of isolated offshore oil and gas platforms. However, its integration makes the analysis of system frequency stability more challenging. Therefore, there is an urgent need to establish a frequency dynamic response model with good interpretability for the isolated grid system of offshore oil and gas platforms with wind power. Based on the improved SFR model, this paper proposes a frequency stability margin index that takes into account both the cumulative effect of abnormal frequencies and the wind power penetration rate. By utilizing the improved SFR model, the system frequency response curve is calculated, and the frequency safety margin of the platform is estimated to determine the maximum wind power penetration rate of the platform in the sense of frequency stability. Finally, the effectiveness of the proposed index is verified through simulations. The results demonstrate that the frequency safety margin index considering the wind power penetration rate can comprehensively evaluate the relationship between the wind power penetration rate and the system frequency stability.