In recent years, the number of buildings that have been damaged due to the loss of the gravity load bearing members, have been increased and the design of structures so that in addition to earthquake, be also resistant against the progressive collapse, has became important. Progressive collapse is the chain of damage in a structure that at least get started with one member of the critical structural failure and continuously transferred to other structural members and finally damage the whole or a large part of the structure. Despite entering the discussion into standards, and even having special codes, but still has many issues in this respect that needs to have a more accurate assessment. Infilled panel is one of these cases. An Infilled panel actually consists of three component: Frame Structural, Filler, The interface between the frame and the filler. The Fillers are used to fill areas between beams and columns that create facades or shear walls and participate in the behavior of building structures in combination with the frame. In addition, at this thesis, progressive collapse with extensive initial damage, removal of the column elements and Adjoining infilled panel, has been discussed, so far, many researches has been done in progressive collapse, initial damage rate limited to remove a column element. at this thesis, with the modeling of several models of steel structures of 3, 6 and 9 floors, as well as, with the ratio of the length of the span to the height of the floor Equal to 1, 1.5 and 2, also with presence and in presence infilled panel of Sandwich panel type, to check of the removal of multi-column and Adjoining infilled panels in the first floor of the structure is considered in four different scenarios. Research shows that as the height of the structure increases in steel structures, the structural reliability increases against the progressive collapse and the damage to the structure decreases in most removal modes. Also, the ratio of the length of