HIV envelope glycoprotein transmembrane subunit gp41 plays a major role in the fusion of viral and target cell membranes. The extracellular region of gp41 consists of N-terminal fusion peptide and downstream N- and C-heptad repeat (NHR and CHR) regions. The peptidesderived from the NHR and CHR regions, designated N- and C-peptides, respectively, have potent inhibitory activity on the HIV mediated cell fusion. C-peptide T-20 has just got the approval of U.S. FDA, which became the first success of one new class anti-HIV agents, named HIV-fusion inhibitors. However, a relatively long peptide such as T-20 suffers from several limitations including proteolytic sensitivity, large dosage, therefore it is unable to produced by gene engineering. Alternately, shorter peptidic fusion inhibitors and active peptides suitable for gene engineering are pursued. In the recent years, this kind of peptide modifications are hot spots in HIV research field and contribute a lot to the inhibitory mechanism of N- and C-peptide.