A facile label-free electrochemiluminescence (ECL) aptasensor was designed for sensitive detection of human immunoglobulin E (IgE) using petal-like CdS nanospheres and Au nanoparticles (AuNPs) as sensing platform. To construct the aptasensor, petal-like CdS nanospheres as ECL emitter were firstly synthesized and immobilized on the chitosan-coated glassy carbon electrode (GCE) surface. Chitosan was coated on the CdS/CS/GCE again with two coating numbers to produce a stable ECL signal and facilitate subsequent AuNPs immobilization. The construction of aptasensor was achieved after IgE aptamer was adsorbed onto the AuNPs. The detection of IgE was performed upon the incubation of the interface with target protein IgE. Under the optimum conditions, the ECL signal decreased depending linearly on the logarithmic value of IgE concentration ranging from 5.0×10(-13) to 1.0×10(-9)M with a regression equation of I=-15254.8-2129.3 logc (R(2)=0.996). The detection limit was experimentally found to be 8.0×10(-14)M. The applicability of the constructed aptasensor was demonstrated in the determination of IgE in human serum samples.