Phycocyanin　(PC)　is　a　natural　fluorescent　protein　which　is　widely　used　in　medical　diagnosis,　biology,　biotechnology,　foods,　and　medicine.　However,　the　disadvantages　in　traditional　purification　methods,　such　as　complicated　preparation　process,　low　yield,　inadequate　quantity,　and　high　price,　limit　its　range　of　application.　In　this　study,　we　established　a　rapid　purification　method　suitable　for　large-scale　production　to　prepare　PC　from　Arthrospira　platensis.　The　membrane　separation　and　two-stage　ammonium　sulfate　precipitation　yielded　PC　with　a　purity　ratio　(A620nm/A280nm)　of　3.65.　This　purification　method　of　PC　proved　to　be　efficient　and　cost-effective　compared　with　previously　reported　methods.　Sodium　dodecyl　sulfate　polyacrylamide　gel　electrophoresis　(SDS-PAGE)　analysis　showed　that　the　molecular　weight　of　α　and　β　subunits　of　PC　was　16.6　and　21.2 kDa.　The　main　molecular　weight　of　intact　PC　determined　through　high-performance　size　exclusion　chromatography　(HPSEC)　was　around　91 kDa,　indicating　that　the　PC　from　A.　platensis　existed　mainly　in　the　form　of　(αβ)3　at　pH 7.0.　The　purified　PC　fluorescent　probe　was　compatible　for　light-emitting　diode　(LED)—charge-coupled　device　(CCD)　fluorescence　density　strip　qualitative　detection　system.　A　relatively　sensitive　novel　fluorescent　test　method　was　developed　for　the　quantitative　detection　of　PC　showing　a　linear　response　to　PC　within　the　range　of　0.07–3.64 μM,　and　with　a　limit　of　detection　of　0.034 μM.　This　method　could　provide　expedient　quantitative　information　and　showed　great　potential　for　rapid　detection　in　environmental　and　food　safety　research.　[Figure　not　available:　see　fulltext.].　©　2018,　Springer　Nature　B.V.