The invention provides a watertight unmanned ship overturn self recovery device, comprising the following parts: high pressure air storage tank (1), inflation control solenoid valve (2), deflation solenoid valve (3), inflation control switch (4), deflation control switch (5), switch controller (6), gasbag (8), battery pack (9), inflation vent pipe (11) and deflation vent pipe (12). The watertightunmanned ship overturn self-recovery device has a simple structure and cheaper devices adopted than ordinary devices. Safety and non-pollution can be achieved by adopting the high pressure air to fill the gasbag. The mechanical switch controller has the advantages of enjoying low cost, easy manufacturing yet full automatic control, maintaining the normal operation of system with low pressure battery pack of only more than ten Volt and avoiding the complex and tedious control mechanism and control system, and thus saving energy and improving the efficiency.