<p>To address the surge instability of high-pressure-ratio compressed air energy storage (CAES) systems under off-design operating conditions during the charging process, this paper proposes a coordinated anti-surge control strategy integrating rotational speed regulation with mass flow control. By incorporating surge boundary constraints into conventional power-tracking control, a dual-objective control method is developed to simultaneously achieve power tracking and maintain compressor stability margins. Subsequently, a comparative analysis is conducted on a compressed air energy storage system consisting of a five-stage compressor train, in which the proposed method is evaluated against a conventional power-tracking control strategy. The results show that, under rated-power conditions, the proposed control strategy maintains a response speed comparable to that of the conventional method, while under low-power conditions, it effectively prevents the operating point from crossing the surge boundary by prioritizing compressor speed regulation in coordination with mass flow correction. Taking the 80% rated-power condition as an example, compared with the conventional control method, the proposed strategy reduces compressor rotational speed by 3.52%, increases mass flow rate by 1.92%, improves the surge margin by 43.8%, and shifts the compressor operating state from the surge region to a stable operating region. Although the control response time is slightly prolonged, it still satisfies the minute-level response requirement of the power grid for energy storage systems. The results indicate that the proposed method can significantly enhance the stability and safety of high-pressure-ratio CAES systems under off-design operating conditions, providing a useful reference for the flexible regulation of energy storage systems in renewable-energy-dominated scenarios.</p>