Key Points: • In-situ stress and natural gas saturation affects fracture process and sediment mechanical properties • Mixed fracture mode tends to be induced while micro fractures and craters were created due to phase change of gas hydrate • Hydraulic fracturing most likely makes pathways favorable for natural gas hydrate Abstract: The utilization of natural gas hydrate (NGH) as fuel is beneficial for meeting increasing energy demands. Hydraulic fracturing is a promising technology for developing NGH resources. Tri-axial fracturing experiments are combined with acoustic emission monitoring to study the feasibility of slickwater fracturing on NGH samples. The results reveal that the NGH samples with high gas hydrate saturation show better fracability; The fluid invasion zone can be found for samples with low gas hydrate saturation, indicating that micro fractures are created inside the sediment. In addition, the fracture morphology is more complex under the strike-slip fault regime than under the normal fault regime for all NGH samples, while a lower horizontal stress difference can increase the fracture complexity and breakdown pressure. The AE monitoring results shows mixed fracture modes exist during NGH fracturing, while the ratio of the tensile and shear fracture mode decrease with a large stress difference. Moreover, the post injection propagation can be observed due to the temperature related mechanical properties of the NGH sample; thus, the phase change of the solid gas hydrate is another important fracture mechanism for NGH fracturing, although the extent of the phase change’s influence on the fracture behavior is closely related to the hydrate distribution and saturation. The fracture mechanical stability observation shows a more rapid strength decrease and large deformation and failure for the NGH samples with high gas hydrate saturations, although the effectiveness is high; thus, it is necessary to balance natural gas production with the geological risk before fracturing.