Abstract: By strength tests of RC continuous slab under concentrated loads, the innuences of transverse assembling seam upon global property of slab; the formation, development and final failure pattern of cracks under loads acting at different positions; the cracking and failure loads of slab and the stress state of one - way slab were studied in this paper. The transverse assembling seam measures adopted in tests can guarantee the globality of slab.Because of the innuences of local effect of concentrated loads, there also exists two - way stress state in one - way slab and causes transverse cracks.