A　new　chemiluminescent　probe　10,10′-dimethyl-3,3′-disulfo-9,9′-biacridine　(DMDSBA)　is　used　ta　label　anti-CEA　anti-body,　the　molar　incorporation　is　1.15-1.32　mole　of　DMDSBA　per　mol　anti-CEA;　the　conditions　of　labeling　reaction,　sandwich　immunoassay　and　chemiluminescent　reaction　are　studied.　Morever,　a　new　double　antibody　sandwich　chemiluminescence　immunoassay　is　firstly　established,　the　linear　calibration　ranges　is　1.5-150.0　ng·mL-1　and　the　detection　limit　is　0.53　ng·mL-1.　This　method　is　used　to　detect　cancer　embryo　antigen　(CEA)　in　human　serum,　the　results　are　well-matched　with　that　of　radio　immunoassay.