Currently, the design of steel structure rarely considers the enclosure wall effect and the quantitative research on the enclosure wall is relatively little. In this paper, the refined finite element model of a steel framework with an enclosure wall was first built by finite element analysis software ANSYS. The numerical simulation results meet the experimental results well considering wallboard contact and friction between the roles. Afterwards, lateral performance was analyzed by taking several key parameters into consideration, including the axial compression ratio, span-depth ratio, siding width, siding thickness and wall open-hole area. The results of this study shows that, when axial compression ratio ranges from 0 to 0.6, the enhancement coefficients of bearing capacity and initial stiffness of the framework with siding boards would range from 1.0 to 2.0; with a constant story height, there is linear positive relation between span-depth ratio and enhancement coefficients; the width of infilled-wallboard is advised as 600mm; different enhancement coefficients should be used when different thicknesses of wall is used; when the hole on wall is strengthened, such influence can be ignored during the design as it has little impact on the whole structure.