Abstract: In order to study the way how to improve the spatial action of precast monolithic composite floor slabs，and would replace the cast-in-place surface layer to reduce the weight of structure，pseudo dynamic tests were used to do elastic contrast tests of 1 /4 scale two-span and three-floor cast-in-place floor-frame shear wall structure( SJ1 model) and precast monolithic floor-frame shear wall structure with X horizontal braces at the bottom of the floor ( SJ2 model) ． The results showed that the X horizontal braces could improve the spatial synergistic action of SJ2 model． Which could meet the forced requirement of the composite floor slabs in steel frame under horizontal force，and reduce the lateral displacement of the frame structure during lateral loading in the elasto-plastic region． From the tests，it was known that the shear of structure was carried mainly by shear wall，it was suggested that the cast-in-place surface layer of precast monolithic composite floor slabs should be canceled in the place of fortification intensity 8． The test results showed that X horizontal braces could more effectively transfer horizontal loads，which provided a beneficial reference for further theoretical research．