The second-order Polarization Mode Dispersion of 22 km and 75 km single mode fiber were measured with Jones matrix eigenanalysis method and Poincare Sphere Method. The parallel component, perpendicular component, depolarization effect, PCD, the statistical characteristics and effects of these components were analyzed. The result is that the perpendicular component had a greater impact on pulse than that of the parallel component in mean. This will be a very helpful researching work for second-order PMD compensation.