The invention discloses a method for locating a steam-turbine generator stator grounding fault according to a phase angle relation of voltage vectors. The method includes: calculating an included angle between a voltage vector of neutral point to ground of a generator and a voltage vector of stator grounding point to ground of the generator; judging whether the generator stator grounding fault occurs at a generator terminal or not; if the generator stator grounding fault occurs inside the generator, calculating a relative proportion a of a grounding point to a neutral point. The method has theadvantages that 1, steam-turbine generator stator grounding fault location can be realized without relying on ground and transition resistance measurement, and an injection type stator ground protection device is not required; 2, the method for locating the steam-turbine generator stator grounding fault is applicable to the steam-turbine generator with the neutral point grounded through high resistance or ungrounded; 3, less required information is required, fault location can be realized only according to a movement report of a stator ground protection device, and application value is realized on the spot.