A modified testing system characterized by full automation,steady operation and high accuracy of strain and stress measurements was developed to determine the cracking tendency of high strength concrete(HSC)in restrained condition at early ages.The shrinkage stress and the tensile creep behavior of HSC at early ages were investigated.The influence of W/C ratio and curing conditions on the early-age shrinkage stress and tensile creep was evaluated.It was found that the lower W/C ratio and drying curing condition resulted in higher shrinkage stress,stress induced tensile creep and greater cracking tendency. A modified testing system characterized by full automation, steady operation and high accuracy of strain and stress measurements was developed to determine the cracking tendency of high strength concrete (HSC) in restrained condition at early ages.The shrinkage stress and the tensile creep behavior of HSC at early ages were investigated. The influence of W / C ratio and curing conditions on the early-age shrinkage stress and tensile creep was was.It was found that the lower W / C ratio and drying curing condition resulted in higher shrinkage stress, stress induced tensile creep and greater cracking tendency.