Abstract: In order to investigate the influence of mineral admixtures on the early shrinkage of concrete under steel bar confinement,the early shrinkage strain and stress of reinforced concrete were measured.Steel ring testing method has been used to investigate the shrinkage crack of different concrete.The test results show that,slag and silica fume obviously increase the early shrinkage of concrete.Limestone powder and fly ash will obviously suppress the early shrinkage,and it shows that the effect of limestone powder is better.Expensive agent can obviously decrease the early shrinkage.It demonstrates that steel ring testing method was a good testing method for checking shrinkage cracking.