Chromium　is　a　metal　with　high　hardness,　and　strong　oxidation　resistance,　doping　chromium　in　the　alloy　will　improve　the　alloy＇s　oxidation　resistance　and　corrosion　resistance.　However,　the　mechanisms　of　chromium　electrodeposition,　electrochemical　oxidation,　and　corrosion　are　still　controversial　and　only　stay　in　the　field　of　electrochemical　research　and　lack　in-situ　data　support.　Therefore,　we　combine　electrochemistry　and　in-situ　Raman　spectroscopy　to　study　the　electrochemical　oxidation　behavior　of　Cr　in　0.5　M　NaOH　solution.　The　results　show　that　the　electrochemical　oxidation　behavior　of　Cr　in　the　alkaline　solution　includes　two　steps.　The　first　step　is　that　the　Cr　layer　loses　six　electrons　and　combines　with　OH-　oxidized　to　CrO42-,　the　second　step　is　CrO42-　enriched　on　the　Cr　layer,　and　the　Cr　layer　loses　six　electrons　again　oxidized　to　Cr2O72-.　We　develop　an　electrochemical　method　for　CrO42-　concentration　detection　in　the　chromium　plating　solution　based　on　this　mechanism.　We　obtain　the　linear　correlation　curve　between　CrO42-　concentration　(0.1　similar　to　2.0　molmiddotL(-1))　and　peak　current　density,　which　has　simple,　fast,　and　broad　linear　range　characteristics.