In　this　paper,　a　sandwich-type　electrochemiluminescent　(ECL)　immunosensor　for　detection　of　microcystin-leucine-arginine　(MCLR)　based　on　gold　nanoparticles　(GNPs)　and　CdS　quantum　dots　(QDs)　was　constructed.　Transmission　electron　microscope　image　(TEM),　photoluminescence　spectra,　ultraviolet-visible　absorption　spectra　were　used　to　characterize　the　CdS　QDs.　The　fabrication　processes　of　the　immunosensor　were　characterized　via　electrochemical　impedance　spectra　(EIS).　A　strong　and　stable　ECL　signal　was　emitted　through　the　electron-transfer　reaction　between　the　electron-injected　CdS　QDs　and　reduced　products　of　S2O82-　in　phosphate　buffered　solution　(PBS,　pH　7.4)　containing　of　0.1　M　K2S2O8　and　0.1　M　KCl.　Under　the　optimum　conditions,　the　ECL　immunosensor　possesses　a　wide　linear　response　to　MCLR　that　ranges　from　0.01　to　50　mu　g/L,　with　a　low　detection　limit　of　0.0028　mu　g/L.　Moreover,　selectivity,　stability,　and　reproducibility　of　the　proposed　immunosensor　were　acceptable.　(C)　2015　Elsevier　B.V.　All　rights　reserved.