The invention discloses a method for accurately obtaining the power control response speed of a main transformer parallel operation wind farm, and solves the problem of distortion of the total power curve obtained by superposing the power curves tested by two power curve testers when a wind farm with large capacity is accessed to a regional power network. A first power tester and a second power tester are connected with a current transformer and a voltage transformer on the high voltage side of a 1# main transformer, the clock deviation [delta]t of the two power testers is obtained, the time scale and active power data sequences [T1, P1) and [T2, P2] recorded in the two power testers are derived, and each value in the T2 time scale sequence derived by the second power tester is substractedby the obtained clock deviation [delta]t of by the two power testers to obtain a time and active power sequence [T20, P2] of the second power tester under a unified time scale; and the power controlresponse speed and precision are calculated. An accurate basis is provided for regional power grid dispatching.