Conventional design practices for reinforced concrete (RC) structural walls in the lower stories of super high-rise buildings involve employing large thickness and dense reinforcement to ensure satisfactory seismic performance. This is necessary to withstand the considerable gravity and seismic forces caused by the superstructure. However, this approach brings a design challenge in engineering practice because excessively thick RC walls not only occupy useable space but also magnify earthquake forces due to the increased self-weight. For this reason, steel truss RC (STRC) composite walls have been developed to address the above-mentioned shortcomings of conventional designs. This paper elucidates the working mechanism of STRC walls under cyclic loading, indicating that these two diagonal embedded steel elements mainly exhibit truss behavior. The working mechanism is further verified through computational models developed in OpenSees with high accuracy and efficiency. Moreover, the design provisions in the current specification are evaluated in terms of the flexural strength and shear strength of STRC walls. Results show that the flexural strength of the design equations for STRC walls in the current specification is underestimated because the contribution of steel trusses is not considered. The findings of this study offer valuable insights into the engineering application of STRC walls.