<p>In deep-sea mining operations, when the mining ship suddenly loses power, it will drift-off under the influence of winds, waves, and currents, which may result in damage to the mining riser system. The drift-off analysis model of the mining ship-riser system is established, and the mechanical characteristics of the mining riser system in the drift-off process as well as the drift-off warning limits are analyzed. The results show that the lower rotation of the hose is the critical factor affecting the safety of the mining riser system during the drift-off process. When the mining vehicle offsets relative to the mining ship along the direction of the ocean currents, the critical limit time is longer compared to other directions of offset. Ocean currents play a key role in determining the critical limit time. During the drift-off process, controlling the mining vehicle to follow the drifting ship at an appropriate speed can help extend the critical limit time to some extent.</p>