Aedes aegypti is a vector for transmitting several tropical fevers. Only the female bites for blood, which she needs to mature her eggs. To find a host, these mosquitoes are attracted to chemical compounds emitted by mammals. The yellow fever mosquito belongs to the tribe Aedini of the dipteran family Culicidae and to the genus Aedes and subgenus Stegomyia. According to one recent analysis, the subgenus Stegomyia of the genus Aedes should be raised to the level of genus. In this Insilico research work, we select the potential protein target (defensin B). The identified peptides are responsible for yellow fever by Aedes aegypti mosquito. We focus on the molecular genetic information of Aedes aegypti, and based on literature studies we model the potential peptide sequence which is responsible for infection by Aedes aegypti in human beings. The modeled 3D structure of the peptide clearly shows the potential antigen binding sites which would be useful in structure based drug designing studies in future.