In view of the shortcomings that the current segmentation of body is less adapt to the crowd and the measurement of body sizes is imprecise, the segmentation method of lower limbs is proposed based on curve fitting of the profile. Firstly, the characteristics extraction of body hip are through iterating curve fitting about hip circle and the segmentation of lower limbs depends on the bifurcation point between legs. Then more than ten sizes of lower limbs are extracted according to the national standards of body sizes. The experimental results show that the method enhances the universality of the subjects and the accuracy of measurement.