The invention relates to a novel pitch control device with low-voltage ride through capability and a control method. The peripheral devices of the pitch control device include a shaft cabinet, a phase-A and phase-B current sensor, a power grid voltage sensor, an absolute or incremental encoder and a variable-pitch motor, and the pitch control device comprises a controller, a power management module, a memory module, a communication module, a current signal-conditioning circuit, a voltage signal-conditioning circuit, a velocity signal-conditioning circuit, a switching value-conditioning circuit, an SVPWM (Space Vector Pulse Width Modulation) output module, an intelligent power module, a rectifier module and a backup battery. The invention also provides a processing method. The pitch control device directly receives the control command sent by a wind turbine main control, and carries out the selection of controller modes and control by detecting the phase-A and phase-B stator current of a generator, the rotation speed of the rotor of the generator and the voltage of a power grid, and moreover, the invention can guarantee the control precision, response speed and reliability of a pitch system and the low-voltage ride through capability of a wind turbine generator system, and ultimately increases the generating efficiency and electricity quality of the whole wind turbine generator system.