Abstract: The engineering structure of rock mass with weak plane in the mining process of metal mine is easy to be damaged by tension and shear. In order to explore the relationship between the support mode and the angle ofweak rock mass，the tensile tests at different angle are carried out for sandstone with weak plane. The results show that: ① There are two kinds of failure modes in thesandstone specimen with weak plane，that is，shear tensile failure and tensile failure；② When the angle between the weak plane and the loading direction reaches 70°，the tensile strength of the precast weak plane specimen with 10 mm is maximum；when the depth of the precast weak plane increases，the peak tensile strength of the disc specimen will move forward with the angle；③ The angle of weak plane will affect the deterioration of the specimen；when the weak plane and the loading direction are around 50°，the 15 mm specimen will break suddenly，with a certain tendency of rockburst；④ The failure mode of the rock mass with weak plane is closely related to its internal weak plane of different angles. The tensile strength experiment for the indoor prefabricatedweak plane specimencan provide guidance for the field construction of the rock mass with weak plane.

Key words: Sand stone, Precast weak plane, Acoustic emission, Failure characteristics, Support mode