A simple, selective and sensitive immunoassay was developed for the determination of human chorionic gonadotrophin (HCG) based on the chemiluminescence resonance energy transfer (CRET). Two kinds of antibodies were used to form a sandwich-type immunocomplex to ensure the selectivity of immunoassay. Based on the simple magnetic separation, amplification feature of gold nanoparticles and CRET phenomenon, this method could be used for highly sensitive determination of HCG without tedious washing steps. Under the optimized conditions, a linear range was obtained when the concentrations of HCG were changed from 0.15 to 5 mIU mL -1 (R = 0.992). This immunoassay could be used for the determination of HCG in serum samples, which provided a promising potential in clinical diagnosis.