Abstract: Disclosed is an electrocardiograph (ECG) lead wire. The left electrode (120) and the right electrode (130) of the ECG lead wire are stacked and enclose an accommodation hole (101) for an electrode contact to pass through. At least one of the left electrode (120) and the right electrode (130) is made of an elastic material and/or is driven by an elastic member, so that the left electrode (120) and the right electrode (130) can move relative to each other under the action of an external force to widen the accommodation hole (101), and can move relative to each other under an elastic action force to narrow the accommodation hole (101). Since the size of the accommodation hole (101) can change, the electrode holder can be adapted to electrode contacts of various sizes on the market and makes same be firmly connected, thereby ensuring the stability and reliability of signal transmission.