Rockburst occurred frequently during deep mining in China. The mechanism of rockburst is very complicated and related to many factors. In order to investigate the influence of moisture contents of rockmass on rockburst, we conducted a series of laboratory rockburst experiments of sandstone under three different moisture contents by the Modified True-Triaxial Apparatus (MTTA),in which the acoustic emission (AE) system was employed to monitor the internal damage of rock mass. A high-speed video camera was utilized to record the detail of rockburst. Based on the experimental results, the AE characteristics, such as AE count,AE energy, and AE frequency, were analyzed. The rockburst process, type, and indensity under different moisture contents were discussed. The research results show that with the increase of moisture contents, rock strength was soften, the elastic and the cumulative damage of the rock were reduced, resulting in a gradual decrease in AE cumulative counts and cumulative energy over the course of rockburst. This study provides an experimental basis and reference for better understanding to the rockburst mechanism and control. The order of investigate the influence of moisture contents of rockmass on rockburst, we conducted a series of laboratory rockburst experiments of sandstone under three different moisture contents by the Modified True-Triaxial Apparatus (MTTA), in which the acoustic emission (AE) system was employed to monitor the internal damage of rock mass. A high-speed video camera was utilized to record the details of rockburst. Based on the The results show that with the increase of moisture contents, rock, the AE characteristics, such as as AE count, AE energy, and AE frequency, were analyzed. strength was soften, the elastic and the cumulative damage of the rock were reduced, resulting in a gradual decrease in AE cumulative counts and cumulative en ergy over the course of rockburst. This study provides an experimental basis and reference for better understanding to the rockburst mechanism and control.