The effects of shrinkage reduction admixture and PVA fiber on the shrinkage and cracking behavior of ultra-light cement composites were studied. The series properties of materials were tested， such as basic mechanical properties， four-point bending properties， free shrinkage， and cracking behavior under ring constraints. The results show that shrinkage reduction admixture can reduce free shrinkage significanly， but the fiber has no effect on the free shrinkage basically. However， due to the inhibitory effect of fiber on cracks， PVA fiber can control crack width and delay the first cracking time more effectively than shrinkage reduction admixture. The inclusion of 6% shrinkage reduction admixture and micro PVA fiber with a length of 12 mm is the most effective way to control the crack width and delay the first cracking time. And studies show that there is a correlation between the residual flexural strength at small deflections in the bending test and the maximum crack width of the fiber-reinforced ULCC at early age.