Taking the southern Shandong Peninsula coast as an example, the circulation patterns and the causes of the gale are explored using the obliquely rotated T-mode Principal Component Analysis and the fifth generation ECMWF reanalysis data (ERA5). There are five main circulation patterns for gale, and the order is the northwest path of the high-pressure type, behind-trough low-pressure trough type, before-trough low-pressure trough type, Jianghuai cyclone type, and north path of the high-pressure type according to the number of gale days, which is consistent with the order of the gale probability for different types. Winter holds the most gale days of high-pressure type (northwest and north path types), spring holds the most gale days of low-pressure trough (before- and behind-trough types), and spring and autumn hold the most gale days of Jianghuai cyclone type. The causes of the northwest path of high-pressure type gale are the combination of the cold advection, cold high-pressure and the momentum downward-transporting. The cause of the north path of high-pressure type gale is the combination of the cold advection and cold high-pressure. The cause of the before-trough low-pressure type gale is the combination of the warm advection, the highpressure at the ocean and the northeast China low. The cause of the behind-trough low-pressure trough type gale is the combination of the cold advection, the cold high-pressure and the northeast China low. The vorticity advection and warm advection before the trough are the key factors for the development and movement of the low pressure. The Jianghuai cyclone moves northeast and results in a large pressure gradient at the south of the Shandong Peninsula, causing the Jianghuai cyclone type gale.