The metal boss is a key load-bearing component of Type IV pressure vessels and usually features an integrated full-skirt structure. Under lifting loads, stress concentration tends to occur in the skirt region, which reduces structural strength and service life. To address this issue, a skirt-notch structure is proposed to improve stress distribution uniformity in the boss skirt during lifting and handling. First, theoretical formulas for the notch number, length, and width were derived from the basic dimensions of the metal boss, and the corresponding parameter ranges were determined. Then, a finite element model of the vessel head section was established, and the Mises stress difference in the boss skirt was adopted as the evaluation index. Finally, the notch parameters were analyzed and optimized using a combination of single-factor analysis and response surface methodology. The results show that the Mises stress difference first decreases and then increases with increasing notch length, width, and number, and the influence of these factors follows the order: number > width > length. Compared with the conventional metal boss, the optimized design with a notch length of 7.8 mm, a width of 16.3 mm, and a notch number of 3 reduces the Mises stress difference by 45.1%, leading to a more uniform stress distribution and improved structural strength and service life.