Based on the actual plate and strip buckling situation in the site and by analyzing the analytic model of
plate and strip buckling，which used to be calculated as a whole，this paper takes the compressive stress region as the plate-shaped buckling deformation region to reflect the actual plate shape situation in the site，and then establishes an analytic calculation model of the outer tension affecting the plate-shaped buckling deformation． Thus，the changes of the critical buckling load and critical width of plate and strip are obtained under different outer tensions，that is，with the increase of tension，the critical buckling load increases while the critical width decreases，which accords well with the actual situation in the site． In order to further verify the analytic calculation result，a finite element calculation model of the plate and strip buckling is established under outer tensions，and the simulation result is consistent with the analytic calculation one．