Statistical method and diagnostic analysis were used to study the Western Pacific Subtropical High (WPSH) ridge position characteristics by taking June 2019 as an example, and the possible mechanism for the southerly position of the WPSH comparing with climate mean state was also investigated. Results show that though the position of WPSH ridge line is generally southerly in June 2019, there are latitudinal differences in its meridional position. Specifically, to the west of 150°E, the position of WPSH ridge line is more southerly than that of the climate mean state, but the opposite is in area between 150°—160°E. Besides, there is a good correspondence between the change of the meridional position of WPSH ridge line and the meridional distribution of the vorticity anomalies nearby. Therefore, the abnormal position of WPSH in June 2019 is attributed to the vorticity anomalies caused by the abnormal perturbations nearby. Additionally, the latitudinal distribution difference of the vorticity anomalies contributes to latitudinal difference of the abnormal position of WPSH. Furthermore, with the complete form of vorticity equation simplified by scale analysis, it is found that the abnormal diabatic heating plays an important role in making the WPSH position southernly in June 2019, while the dynamic factor contributes more to the northward movement of WPSH ridge line to the east of 150°E.