To study the quantitative detection method of T-wave alternans (TWA), we analyzed the relationship between the graphic mode of Poincare scatter and TWA, and proposed ‘horizontal search algorithm' to complete graphic processing. Then, based on the shape of Poincare scatter, we took Axial_ratio as the final index. Through Matlab simulation, Axial_ratio was compared with the results of spectral method (SM) and appropriate threshold value was selected to recognize the TWA. The results showed that Axial_ratio could accurately detect the TWA.