The present invention relates to a series of peptides, and a peptide-siRNA complex. The peptide and the siRNA are coupled non-covalently. The peptide based complex effectively enhances delivery of siRNA molecules into the cells and release of siRNA in the cell, and improves siRNA mediated gene silencing efficiency of cellular targets. The invention also relates to a pharmaceutical composition comprising the complex, and a use of the complex in the therapy field of gene.