Time-varying　cable-force　identification　is　fundamental　for　assessing　the　fatigue　damage　of　stay　cables.　This　study　proposes　a　novel　method　for　real-time　time-varying　cable　force　identification.　This　method　updates　the　cable　vibration　signals　through　the　sliding　window　and　employs　adaptive　chirp　mode　decomposition　(ACMD)　to　identify　the　instantaneous　frequencies　of　the　cables.　Finally,　the　cable　forces　were　calculated　based　on　the　taut　string　theory.　The　novelty　of　this　study　lies　in　the　introduction　of　ACMD　to　enhance　the　accuracy　of　cable-force　identification,　while　adaptively　determining　the　key　parameters　of　ACMD　based　on　the　scale　space　peak　picking　(SSPP)　algorithm.　The　effectiveness　of　this　method　was　been　verified　through　numerical　models,　with　the　results　showing　that　the　maximum　relative　error　in　cable-force　identification　was　0.87%.　Furthermore,　this　method　was　successfully　applied　to　a　sea-crossing　cable-stayed　bridge,　demonstrating　its　ability　to　assess　cable　force　accurately.