Using the density-functional theory and the non-equilibrium Greens function method, we investigated the electronic transport properties and rectifying performance of three different molecular devices based on different molecular configurations of the same molecule species. The results show that rotation of a mid-benzene ring (bonding bridge—πbridge) can change the delocalization of a molecular orbital and thus change their transport property and rectifying performance. This finding suggests that the variation of the bonding bridge orientation can control the rectifying performance of a molecular device effectively. It is of significance for designing a novel molecular rectifier.