This study extensively investigates T-shaped axial compression members with varying wing-flange width-to-thickness ratios, focusing primarily on the influence of section width-to-thickness ratio and effective width on the sectional resistance. Based on the AISC 2017 specifications, assuming the overall component is a stable member, the study analyzes the impact of varying the wing-flange width-to-thickness ratio on the sectional stability and resistance of the structure. Especially for slender sections that exceed the width-to-thickness ratio limits specified in AISC 2017, it is necessary to consider the sectional resistance affected by local buckling. Therefore, the concept of reduced section is proposed - effective width constraint, which accurately reflects the actual resistance of the component. As the T-shaped section is a singly symmetric profile, a detailed analysis will be conducted on flexural buckling (FB) and flexural-torsional buckling (FTB) under various wing-flange width-to-thickness ratio conditions. Through the analysis of these two buckling behaviors, a more comprehensive understanding of the stability and resistance of T-shaped section members under different wing-flange width-to-thickness ratio conditions can be achieved. This study contributes to the understanding of the stability and cross-sectional solid of T-shaped members, providing insights for the design analysis of AISC2017-specified T-shaped section components. Particularly, it focuses on research related to section width-to-thickness ratio, slender section considerations, and sectional resistance. Further research is conducted on the issue of reduced resistance due to excessively slender cross-sections. This not only aids in better understanding the resistance of cross-sections but also provides practical design references. Therefore, this study holds research value regarding the analysis of the width-to-thickness ratio design for T-sections in the AISC 2017 specification, particularly when considering factors related to slender sections and cross-sectional resistance.