The embodiment of the invention provides a device and a method for compensating polarization mode dispersion in optical communication. The method mainly comprises the steps of: detecting polarization state data and optical power of an optical signal in an optical transmission link, regulating the polarization state data according to the optical power, calculating to obtain the polarization degreevalue of the optical signal according to the regulated polarization state data, calling a jitter-based particle swarm optimization algorithm used as a search algorithm according to the polarization degree value, calculating to obtain a corresponding control voltage when the polarization degree in the optical transmission link reaches the maximum. A control compensation unit compensates the polarization mode dispersion in the optical transmission link by using the control voltage. By using the invention, the accuracy of the acquired polarization degree information is effectively improved, the adopted search and track algorithm is not easy to involve in the local extremum; meanwhile, the steps of iteration during searching and tracking are less, thereby carrying out effective compensation according to the polarization mode dispersion in the optical transmission link.