In this article，an unique electrochemiluminescence sensor was built to study DNA damage due to perfluorooctanoic acid（PFOA）.First of all,combining the special properties of quantum dots（QDs） and nano gold particles（NG）,the quantum dots-nano gold（QDs-NG） composite particles was prepared.Then,the calf thymus DNA（ct-DNA） was modified onto the surface of glassy carbon electrode（GCE）.After dried in the incubator,the QDs-NG composite particles was dropped onto the electrode.In this way,the electrochemiluminescence sensor based on QDs-NG particles was established.It was used to study the enhancement effect of QDs luminous intensity based on NG particles.And further,the DNA damage due to PFOA was also investigated using the electrochemiluminescence sensor.The atomic force microscope（AFM） and X ray photoelectron spectroscopy（XPS） were also adopted to characterize the surface morphology of modified electrode.The results showed that the existence of the NG particles had obvious enhancement effect on the luminous intensity of QDs，and the electrochemiluminescence intensity was increased about four times.On the other hand,after the interaction between PFOA and ct-DNA at 37 ℃,electrochemiluminescence intensity was decreased to a great degree,which indicated that PFOA caused DNA damage.