A novel detection method of a tumor marker alpha-fetoprotein(AFP) in human sera via capillary(electrophoresis) immunoassay coupled with chemiluminescence detection(CEIACL) was established.After a simple non-competitive immunoassay procedure,seras were directly injected into capillary for electrophoresis with chemiluminescence reaction of luminol and H2O2 catalyzed by horseradish peroxidase and enhanced by(p-iodophenol).The detection limit(S/N=3) of AFP is 0.85 μg/L.The CEIACL method proposed was successfully applied to the sensitive detection of AFP in human sera,which coincides with the results detected by Beckman automatic CL analyzer-access IA system.