Abstract：Both of TAW-3000 servo-controlled test machine and PCI-2 acoustic emission (AE) monitor system are used during the uniaxial compressive and the AE tests on argillaceous siltstone under dry and water-saturated states. The difference of rock rupture mechanics and AE characteristics on two moisture contents has been developed, as well as the damage evolution process based on AE sign. The results show that the strength, elastic modulus and the destruction level of water-saturated specimen are lower than those in dry specimen. The dry specimen is typical of brittle fracture, while the water-saturated specimen undergoes plastic damage. AE events rate level and AE events rate peak value are lower than those in dry specimen. Before the fracture of water-saturated specimen, a unique quiet region in the growth of AE events rate curve of will appears, which could be regarded as a precursor in the practical engineering. The damage evolution equation based on the relative AE accumulative events is set up and derived. According to the fitted values of β in Weibull distribution, the degree of micro-unit strength concentrated distribution in dry specimen is stronger than those in water-saturated specimen, namely water causes a certain degree of damage to argillaceous siltstone.