An　integrated　immunodetection　platform　employing　a　simple,　reusable,　centrifugal　microchannel　array　chip　and　a　smartphone　as　detection　unit　was　developed.　The　applicability　of　the　platform　to　the　detection　of　HIV　p24　antigen　was　demonstrated.　The　microchip　was　made　of　polycarbonate　and　contained　4　x　8　zigzag　micro　channels.　After　the　monoclonal　antibody　of　HIV　p24　was　adsorbed　onto　the　channel　surfaces,　HIV　p24　was　introduced　into　the　microchannel　to　react　with　the　antibody.　A　biotin　linked　polyclonal　antibody　was　then　brought　in　to　react　with　HIV　p24,　and　SP80　(containing　streptavidin　and　horseradish　peroxidase)　was　introduced　to　react　with　the　biotin.　Finally,　a　solution　containing　3,3＇,5,5＇-tetramethylbenzidine　and　other　reagents　was　passed　through　the　above　channels,　horseradish　peroxidase　catalyzed　the　oxidation　of　tetramethylbenzidine　(to　3,3＇,5,5＇-　tetramethylbenzidine　diamine)　forming　a　dark　color.　The　color　intensity,　indicating　HIV　p24　antigen　quantity,　was　then　photographed　via　a　smartphone,　and　the　color　of　each　microchannel　was　processed　via　a　computer　to　determine　the　HIV　p24　antigen　concentration.　Under　the　optimized　conditions,　limits　of　detection　(LODs)　of　0.17　ng/ml　and　0.11　ng/ml　were　obtained　for　p24　antigen　in　a　buffer　solution　and　human　serum,　respectively.　Channel　washing/rinsing　was　implemented　via　a　centrifugal　force.　An　economic　portable　centrifugal　device　that　could　accommodate　up　to　4　microchips　was　assembled,　and　multi-step　solution　loading　and　rinsing　involved　in　this　sandwich　immunoassay　were　performed　conveniently.　The　microchip　could　be　reused　after　a　simple　regeneration　process.　The　low-cost　polycarbonate　microchip　and　centrifugal　device　together　with　the　simple　but　efficient　operation　make　the　method　a　promising　tool　for　HIV　screening　in　resource　limited　areas.