There is increasing interest for chemiluminescence (CL) detection with the characteristics of simplicity, low cost and high sensitivity, especially wide application of enhancersin CL detection to increased signals, prolonged luminescence time and enhanced intensity. In this review, the applications of primary enhancers and secondary enhancers were mainly described in the horseradish peroxidase–luminol system of CL enzyme immunoassay for light delay in the course of the reaction with improved sensitivity. The present review on enhancers covers the papers since 1983. Future research needs to develop novel enhancers with less interference and better performance. With wide utilization of enhancers in the CL system, the CL immunodetection technology showed a good potential and wide development prospects in food and medicine fields.