Earthquake may cause severe damage to buildings and wounded or dead harm to people. In order to ensure the structural safety of buildings, the lateral limit load capacity of building structure is studied concentrately. In this thesis, the computer program SAP 2000 version 7 was used to analyze the elastic-plastic behavior of two steel frames connected with bridges. The displacement and collapse of buildings linked by corridor in different height, number, length and width and suffered to earthquake were studied. The result showed that the ultimate load of building will be raised if bridge is supported by two inclined rods. But the displacement of building will be decreased when building is subjected to lateral force, such as earthquake load and wind load.