Abstract: Method and device for detecting DNA by using electrochemiluminescence, wherein a probe DNA is immobilized on a chip, a target DNA is placed on the chip having the probe DNA immobilized thereon, for hybridization of the probe DNA and the target DNA, and an intercalator is fixed to the hybridized DNA. Then, an electrochemiluminescent reaction fluid is introduced into the chip having the DNA with a fixed intercalator, a preset voltage is applied to the chip for causing reaction between the intercalator and the electrochemiluminescent reaction fluid, and a light from the reaction is detected, and analyzed, whereby making a DNA detection process fast and simple, and a system of the device for detecting a DNA simple, to permit a device price low, and the DNA detection accurate.