Abstract: Four reinforced masonry walls of different types of steel tie bars，whose outer wythes were tested subjected to an out-of-plane loading，were tested under horizontal low cyclic loading. The outer wythescooperation with the inner ones and mechanical behavior of the outer wythes were studied and analyzed. The results of the test showed that the outer wythes cooperated well with the inner ones; the steel tie bar made great contribution to the out-of-plane bearing capacity of the outer withes. Of all the four designed types of steel tie bars，Z-ties worked the worst，which can be used in multilayer buildings and are suggested not to be used in high-rise buildings. However，the other three types can be used in high-rise buildings and considering construction convenience，among them the rectangular ties are the best choice. Seismic behavior under large earthquake of intensity 7 and intensity 8 and the wind load-bearing capacity of the outer wythes of a 20 stories building in Changsha are sufficient.