By introducing a two-stage polarization mode dispersion (PMD) compensator after a optical fiber link with a large PMD,over 270 ps first-order and 2 000 ps~2 high-order PMD was compensated.The results show that the two-stage compensator can be used to PMD compensation in the 20 Gb/s optical time division multiplexing system with 60 km high PMD fiber.After compensating,the 270 ps DGD is changed into max.7 ps.Moreover,the tunable FBG has a function of dispersion compensation. By introducing a two-stage polarization mode dispersion (PMD) compensator after a optical fiber link with a large PMD, over 270 ps first-order and 2 000 ps ~ 2 high-order PMD was compensated. The results show that the two-stage compensator can be used to PMD compensation in the 20 Gb / s optical time division multiplexing system with 60 km high PMD fiber. After compensating, the 270 ps DGD is changed into max.7 ps.Moreover, the tunable FBG has a function of dispersion compensation.