The off-grid wind-powered seawater desalting system is powered by the independently operating wind power generation system. A variable working condition design has been adopted for the seawater desalting system. Therefore, the control system of the seawater desalting system is self-adaptive to the wind power generation capacity and it adjusts the self-operating mode to meet the requirements that wind power generation capacity fluctuates in response to wind energy, realize seamless connection with wind power generation system and guarantee stable quality of the desalted water under various working conditions.