An individual pitch control method for a large wind turbine generator system, comprising decomposing an individual pitch control into a collective pitch control process and a deviation pitch control process, wherein the collective pitch control process comprises controlling a rotating speed of a rotor based on a classic PI control by detecting a generator rotating speed ( ω g), obtaining a rotating speed deviation (Δ ω) by subtracting a reference rotating speed (ω ref) from the generator rotating speed ( ω g), and obtaining the collective pitch angle ( β c) desired to be output for the collective pitch control according to the following Laplace formula: β c s Δ ω s = K c sT c 1 + sT c, where K c is a proportion coefficient of a PI controller, and T c is an integration time constant of the PI controller, wherein the individual pitch control method further comprises a deviation pitch control process, the deviation pitch control process comprising: 1) transmitting measured load values ( M y 1, M y 2, M y 3) at root part of the three blades and a azimuth ψ of the rotor to a main controller, performing a Park transformation on the load values ( M y 1, M y 2, M y 3) at root part of the three blades by the main controller, and obtaining the nodding load component M tilt and the yaw load component ( M yaw); 2) obtaining pitch angles β 1 cm β 2 cm desired to be output on d-axis and q-axis respectively according to the following Laplace formulae: β 1 cm s M titl s = K d sT d 1 + sT d, β 2 cm s M yaw s = K q sT q 1 + sT a, where K d and K q are proportion coefficients of a PI controller, and T d and Tq are integration time constants of the PI controller, wherein the d-axis and q-axis are axes of a fixed coordinate system of a hub; 3) obtaining the deviation pitch angles ( β ' 1, β ' 2, β ' 2) desired to be output for the deviation pitch control by Park inverse transforming the pitch angles β 1 cm β 2 cm desired to be output on d-axis and q-axis; 4) obtaining pitch angles ( β 1, β 2, β 3) desired to be output for the individual pitch control according to the collective pitch angle ( β c) desired to be output for the collective pitch control and the deviation pitch angles ( β ' 1, β ' 2, β ' 2) desired to be output for the deviation pitch control: β 1 = β ' 1 + β c, β 2 = β ' 2 +β ' c, β 3 = β ' 3 + β c; and 5) implementing the pitch control by controlling operations of respective pitch control servo motors according to the pitch angles ( β 1, β 2, β 3) desired to be output, characterized in that before the step of obtaining a rotating speed deviation Δω by subtracting a reference rotating speed ωref from the generator rotating speed ωg, the method further comprises a step of filtering the generator rotating speed ( ω g) according to the following Laplace formula: ω gf s ω g s = ω 1 2 s 2 + 2 η 1 ω 1 + ω 1 2 ⋅ 1 + 2 η 2 s / ω 2 + s 2 / ω 2 2 1 + 2 η 3 s / ω 3 + s 2 / ω 3 2; where ω gf is a post-filtering generator rotating speed, ω 1 is a natural frequency of a low-pass filter, η 1 is a damping ratio of the low-pass filter, ω 2 and ω 3 are natural frequencies of a notch filter, and η 2 and η 3 are damping ratios of the notch filter. 1) transmitting measured load values ( M y 1, M y 2, M y 3) at root part of the three blades and a azimuth ψ of the rotor to a main controller, performing a Park transformation on the load values ( M y 1, M y 2, M y 3) at root part of the three blades by the main controller, and obtaining the nodding load component M tilt and the yaw load component ( M yaw); 2) obtaining pitch angles β 1 cm β 2 cm desired to be output on d-axis and q-axis respectively according to the following Laplace formulae: β 1 cm s M titl s = K d sT d 1 + sT d, β 2 cm s M yaw s = K q sT q 1 + sT a, where K d and K q are proportion coefficients of a PI controller, and T d and Tq are integration time constants of the PI controller, wherein the d-axis and q-axis are axes of a fixed coordinate system of a hub; 3) obtaining the deviation pitch angles ( β ' 1, β ' 2, β ' 2) desired to be output for the deviation pitch control by Park inverse transforming the pitch angles β 1 cm β 2 cm desired to be output on d-axis and q-axis; 4) obtaining pitch angles ( β 1, β 2, β 3) desired to be output for the individual pitch control according to the collective pitch angle ( β c) desired to be output for the collective pitch control and the deviation pitch angles ( β ' 1, β ' 2, β ' 2) desired to be output for the deviation pitch control: β 1 = β ' 1 + β c, β 2 = β ' 2 +β ' c, β 3 = β ' 3 + β c; and 5) implementing the pitch control by controlling operations of respective pitch control servo motors according to the pitch angles ( β 1, β 2, β 3) desired to be output,