To address the problem that traditional energy storage frequency regulation strategies struggle to adapt to the differentiated requirements across multiple frequency regulation stages in high-penetration wind power systems, as well as the risk of secondary frequency drops due to state-of-charge (SOC) violations, a multi-stage dynamic frequency regulation strategy for wind-storage integrated systems considering SOC-adaptive modulation is proposed. First, the equivalent frequency response characteristics of the system are analyzed, and the differences in control requirements among different frequency regulation stages are clarified. Second, a bidirectional asymmetric Sigmoid-type adaptive modulation function is constructed to achieve smooth switching and adaptive matching of control parameters for the wind-storage coordinated frequency regulation across different stages. Finally, a time-domain simulation model is built for multi-condition comparative verification. The results show that, compared with conventional frequency regulation schemes, the proposed strategy reduces the maximum rate of change of frequency from 0.58 Hz/s to 0.51 Hz/s. Under a low-SOC condition with an initial SOC of 0.3, it improves the frequency nadir by 0.03 Hz while maintaining the SOC above the 15% safety threshold throughout the process. This effectively reduces the risk of secondary frequency drop and improves both the system frequency security margin and the long-term frequency regulation capability of the energy storage system.