Objective: To investigate the significance of the valvular incompetence of the popliteal vein in primary chronic venous insufficiency (PCVI) of the lower extremities. Methods: The data of 268 PCVI patients that met the inclusion criteria were divided, according to the lesion’s location, into sapheno-femoral valve incompetence group, superficial femoral vein valve incompetence group, popliteal vein valve incompetence group, and femoral-popliteal vein valve incompetence group, with 67 cases in each group. The differences in Kistner’s classification, venous segmental disease score (VSDS), clinical (C) classification, venous clinical severity score (VCSS) and venous disability score (VDS) among the groups were determined. Results: The Kistner’s classification, VSDS, C classification, VCSS and VDS in popliteal vein valve incompetence group were all higher than those in sapheno-femoral valve incompetence group or superficial femoral vein valve incompetence group, with all differences achieving statistical significance (all P<0.05), but were all lower than those in femoral-popliteal vein valve incompetence group, with some differences reaching statistical significance (Kistner classification and VSDS) (both P<0.05). The correlation between lesion’s location and Kistner’s classification had statistical significance (r=0.926, P=0.000), and the correlationship between Kistner’s classification and C classification were affected by the factors such as sex, age, and course of disease (all P<0.05). Conclusion: Valvular incompetence of the popliteal vein can aggravate the venous reflux in lower limbs, expand the range of venous disease, exacerbate the clinical symptoms and decrease working ability.