Abstract: The subcritical energy blanket is an important component of the fusion-fission hybrid reactor. The mechanical characteristic analysis of the subcritical energy blanket is the key to ensure the normal operation of the whole reactor. In this paper, the preliminary mechanical analysis for the parts including the first wall and the support structure of the subcritical energy blanket is carried out. Accordingly, the maximal stress value, the stress distribution contours and the deformation distribution contours are obtained. The maximal stress of the support structure is located at the connection between the stiffener and the cylindrical pin and the value is 310.2 MPa. The maximal Tresca stress of the first wall is located at the corner of the U shaped flow channel and the value is 240.7 MPa. In the light of the strength and stiffness norms, the calculation results show that the structure of the subcritical energy blanket can satisfy the strength and stiffness requirements.