The invention discloses a method for constructing a minimum-guarantee power grid in a coastal region. The method comprises the following steps of acquiring key user information of a target city located in a coastal region; obtaining power supply channel information of each key user in the key user information; inquiring the high-reliability channel part of each power supply channel according to the power supply channel information, and determining the initial node of each high-reliability channel part; and setting an energy storage power station at the initial node of the high-reliability channel part according to the power supply requirement of the key user corresponding to the high-reliability channel part, wherein the energy storage configuration of the energy storage power station is matched with the power supply requirement. Therefore, the technical problem of how to build a " lifeline " channel for high-reliability power supply of the minimum-guarantee power grid of the coastal region and construct a local power grid for self-balancing operation under a typhoon disaster can be solved.