A method for differential control of variable pitch, comprising: acquiring a first control parameter and a second control parameter respectively by means of a static energy deviation PI control method; acquiring a third control parameter using a dynamic energy deviation; and controlling, by a proportion integration differentiation, PID, controller, a wind generator according to the first control parameter, the second control parameter and the third control parameter by taking a wind wheel measurement rotating speed and a wind wheel reference rotating speed as inputs, so that the wind wheel measurement rotating speed follows the wind wheel reference rotating speed, wherein the first control parameter is acquired according to a formula: K P = 2 I drivetrain Ω ref ζω G gearbox − ∂ P ∂ θ wherein G gearbox is the gearbox transmission ratio, Ω ref is the wind wheel reference rotating speed, ω is the nature frequency of a second-order differential system of the wind wheel reference rotating speed with a unit of rad/s, ζ is the damping, I drivetrain is the moment of inertia in drive train of a wind generator, P is the absorbed power by a wind wheel with a unit of W, and θ is the variable pitch angle; the second control parameter is acquired according to a formula: K I = I drivetrain Ω ref ω 2 G gearbox − ∂ P ∂ θ wherein G gearbox is the gearbox transmission ratio, Ω ref is the wind wheel reference rotating speed, ω is the nature frequency of a second-order differential system of the wind wheel reference rotating speed with a unit of rad/s, ζ is the damping, I drivetrain is the moment of inertia in drive train of a wind generator, P is the absorbed power by a wind wheel with a unit of W, and θ is the variable pitch angle; and the third control parameter is acquired according to a formula: K d = I drivetrain Ω − Ω ref G gearbox ∂ P ∂ θ wherein G gearbox is the gearbox transmission ratio, Ω is the wind wheel measurement rotating speed, Ω ref is the wind wheel reference rotating speed, ω is the frequency, and ζ is the damping, P is the absorbed power by a wind wheel with a unit of W, and θ is the variable pitch angle. acquiring a first control parameter and a second control parameter respectively by means of a static energy deviation PI control method; acquiring a third control parameter using a dynamic energy deviation; and controlling, by a proportion integration differentiation, PID, controller, a wind generator according to the first control parameter, the second control parameter and the third control parameter by taking a wind wheel measurement rotating speed and a wind wheel reference rotating speed as inputs, so that the wind wheel measurement rotating speed follows the wind wheel reference rotating speed, wherein the first control parameter is acquired according to a formula: K P = 2 I drivetrain Ω ref ζω G gearbox − ∂ P ∂ θ wherein G gearbox is the gearbox transmission ratio, Ω ref is the wind wheel reference rotating speed, ω is the nature frequency of a second-order differential system of the wind wheel reference rotating speed with a unit of rad/s, ζ is the damping, I drivetrain is the moment of inertia in drive train of a wind generator, P is the absorbed power by a wind wheel with a unit of W, and θ is the variable pitch angle; the second control parameter is acquired according to a formula: K I = I drivetrain Ω ref ω 2 G gearbox − ∂ P ∂ θ wherein G gearbox is the gearbox transmission ratio, Ω ref is the wind wheel reference rotating speed, ω is the nature frequency of a second-order differential system of the wind wheel reference rotating speed with a unit of rad/s, ζ is the damping, I drivetrain is the moment of inertia in drive train of a wind generator, P is the absorbed power by a wind wheel with a unit of W, and θ is the variable pitch angle; and the third control parameter is acquired according to a formula: K d = I drivetrain Ω − Ω ref G gearbox ∂ P ∂ θ wherein G gearbox is the gearbox transmission ratio, Ω is the wind wheel measurement rotating speed, Ω ref is the wind wheel reference rotating speed, ω is the frequency, and ζ is the damping, P is the absorbed power by a wind wheel with a unit of W, and θ is the variable pitch angle.