We have performed global structural optimizations for neutral lead clusters Pb-n (n = 2-20) by using a genetic algorithm (GA) coupled with,a fight-binding (TB) potential. The low-energy structures identified from a GA/TB search were further optimized at the DFT-PBE level. The calculated results show that the Pb-n (14 < n <= 20) clusters favor compact spherical structures with hexagon and pentagon rings. These structures are different from those of Si-n, Ge-n, and Sn-n, clusters which favor prolates in the same size range. The binding energies, second differences in energy, and fragmentation behaviors of the Pb-n, clusters were also discussed. Pb-n (n = 4, 7, 10, 13, 15, and 17) clusters are found to be special stable clusters, which is in good agreement with the experimental results.