A　high-performance　chemiluminescence　immunoassay,　with　long-term　durability,　good　precision　and　time-saving,　was　proposed　for　the　detection　of　free　17　beta-estradiol　(E2)　in　human　serum.　Ninety-six　microplates　were　coated　with　bovine　serum　albumin　conjugated　E2　antigen　as　solid　phase　for　the　immunoassay.　The　E2-BSA　antigen　coated　on　the　microplate　and　the　E2　antigen　in　the　sample　competed　for　the　binding　sites　on　the　horseradish　peroxidase　(HRP)　labeled　anti-E2　antibody.　Chemiluminescence　reaction　was　subsequently　carried　out　by　HRP　catalyzing　luminol-H2O2　substrates,　and　the　chemiluminescence　intensity　was　inversely　proportional　to　the　amount　of　analyte　in　human　sera　samples.　The　concentration　of　immunoreagents,　immunoreaction　time,　and　other　relevant　variable　conditions　upon　the　immunoassay　were　studied　and　optimized.　The　proposed　method　exhibited　detection　limit　as　low　as　5.94　x　10(-3)　mu　g　center　dot　L-1　in　a　linear　detection　range　from　0.01　to　1.00　mu　g　center　dot　L-1,　good　recoveries　between　105%　and　108%,　and　high　precision　with　intra-　and　inter-assay　coefficients　between　7.9%　and　14.3%.