The present invention discloses an electric system small disturbance stability discrimination method caused by wind power fluctuation. The method comprises the steps of: the step 1: establishing a wind frequency distribution function of a wind power plant; the step 2: establishing power output probability distribution of the wind power plant according to the wind frequency distribution function ofthe wind power plant obtained in the step 1; the step 3: employing an electromechanical transient simulation analysis method, and calculating and obtaining an electric system small disturbance key oscillation mode and a key characteristic root; the step 4: performing series expansion of the key characteristic root to obtain a probability distribution function of random change of the real part ofthe key characteristic root based on the key characteristic root obtained in the step 3; and the step 5: drawing a characteristic value real part probability distribution graph based on the a probability distribution function of random change of the real part of the key characteristic root obtained in the step 4, and discriminating the electric system small disturbance stability characteristic according to the characteristic value real portion probability distribution graph. The electric system small disturbance stability discrimination method caused by wind power fluctuation has good adaptability for long-term development of the electric system.