Monitoring　the　state　of　charge　(SOC)　of　the　battery　can　prevent　overcharge　and　over-discharge　for　improving　battery　life.　This　study　considers　the　effect　of　battery　aging　on　the　SOC　and　uses　a　model　based　on　a　gated　recurrent　unit　(GRU)　network　to　predict　the　state　of　health　(SOH).　Furthermore,　the　predicted　SOH　with　voltage,　current,　and　temperature　is　adopted　as　the　input　of　another　GRU-based　model　to　predict　SOC.　The　results　show　that　the　proposed　method　has　a　higher　prediction　accuracy　than　other　methods.　©　2022　IEEE.