Abstract:With the popularity of treadmill graded exercise test and Holter ECG monitoring technology, the probability of mixed wrong connections between upper and lower limb lead wire or left and right hand lead wire of 12 lead simultaneous monitoring ECG increases gradually. Those wrong connection ways are intricate and the graphs are illegible. Taking the limb-lead ECG of a 35-year-old healthy male adult for example, diagrammatize the ECG lead polarity and the tracing order of channels separately in 6 connection ways of lead wire, the right way and 5 wrong ways, especially display the mixed wrong connection ways between the upper and lower limb lead and the ECG representations.