The deepwater drilling riser is an important structure which is used for connecting the offshore drilling platform and the subsea wellhead. During service, the riser is subjected to severe loads which will result in complex mechanical behavior. However, the marine environment of deepwater drilling engineering is harsh, complex and changeable, especially in extreme situations such as typhoon. In order to protect the wellhead and the drilling platform, disconnection operation between the riser and the wellhead must be carried out. Thus, the riser is in the state of suspended. In addition, emergency evacuation will be implemented when the severe weather occurs. Generally, the hard hang-off mode is usually selected as an operation mode of the riser evacuating from severe weather. Therefore, it is of great significance for the safety control of deepwater drilling to study the mechanical behavior of riser in hard hang-off mode. In this paper, the mechanical model of a hard hang-off riser is regarded as a cantilever beam fixed at the top end and free at the bottom end. The static mechanical response of the suspended riser under different evacuating speed, evacuating directions and different suspended length are studied. Then, the feasibility of the allowable speed and the maximum allowable suspended length when the riser evacuates from typhoon are figured out. Finally, the conclusions are drawn based on the analysis. This study has reference value for safety control of the deepwater drilling riser during emergency evacuation.