Abstract:This paper selects three typical cases, starting with two-dimensional time scatter plot, Lorenz scatter plot and difference scatter plot, the regularity of threedimensional Lorenz scatter plot was explored step by step. The three-dimensional Lorenz scatter plot characteristics of atrial premature beats, atrial premature beats not conducting down, premature ventricular contraction, interpolated premature ventricular contraction and ventricular reciprocal beats were analyzed and summarized. The internal relations between two-dimensional Lorenz scatter plot, difference scatter plot and three-dimensional Lorenz scatter plot were compared. The results show that three-dimensional Lorenz scatter plot integrates all the advantages of two-dimensional Lorenz scatter plot and twodimensional difference scatter plot. A newly provided zOx surface exhibits symmetrical features(symmetry for constant velocity line). This reflects the regularity of separated RR intervals and the classification of RR intervals is exhibited in the most beautiful way. This is a new function that all of two-dimensional Lorenz scatter plots do not have. Another important theoretical significance of threedimensional Lorenz scatter plot is the verification of the important values of twodimensional difference scatter plot—the latter is equivalent of xyz surface of the former.