The invention discloses a determination method for over-temperature shut-down of a water chilling unit in an offshore wind farm. The determination method comprises step A of obtaining the three-phase real-time temperature and real-time power of a winding of a fan generator, step B of obtaining the real-time temperature of a transmission bearing of the fan generator, step C of obtaining the rated power recorded as Pe, of a fan, setting the limit value of the cooling water inlet temperature of the generator to Tlin, and setting the limit value of the cooling water outlet temperature of the generator to Tlex, step D of calculating a fault determination value F through a calculation module, and step E of setting a fault critical value Tset, and carrying out comparative judgment on the fault critical value Tset and the fault determination value F. According to the determination method for over-temperature shut-down of the water chilling unit in the offshore wind farm, which is disclosed by the invention, faults are determined according to the three-phase active power and the three-phase winding temperature of the fan generator, and the two-end temperatures of a drive shaft, the running condition of the fan generator can be accurately reflected, and fault shut-down can be reduced, thus the utilization rate of wind power resources is increased.