Abstract：Creep characteristic is one of the most important mechanical characteristics of rock. It controls the stability of rock engineering. Under step load condition，the creep test of red-bed soft rock which was collected in the seventh tunnel of Yintao water transmission engineering in Gansu is performed by using the CSS-44100 electronic servo testing machine. Based on scientific interpretation and analysis of test data，red-bed soft rock has remarkable creep characteristics and Burgers creep model can be applied to characterize the creep of red-bed soft rock. The effect of water content upon strength and creep characteristic are studied it shows that instantaneous strength decreases with increasing of water content. The higher the water content is，the more creep deformation and the time that need reaching steady state and the bigger the rate of creep are. The test results show that the creep testing curves of red-bed soft rock are coincident well with the theoretic curves and the Burgers creep model can be applied to characterize the creep properties of red-bed soft rock.
