【正】 A self-similar-structure shell modct (SSM) is proposed to extend the conven-tional shell model (SM) calculation to study halo nuclei.The exotic structures of <sup>11</sup>Liand <sup>6</sup>He nuclei are reproduced by means of SSM.The neutron halo of <sup>11</sup>Li comes fromthe spin-orbit term and the thick neutron skin of <sup>6</sup>He arises from the different quantumnumbers N<sub>n</sub> and N<sub>p</sub>(N=2n+1) in SSM.