In this article, Raman bond polarizability of trans-2,3-epoxybutane is derived from its Raman intensity, and the charge distribution of its Raman excited virtual state is obtained. The differential bond polarizability is also obtained from its Raman optical activity (ROA) intensity. The Raman chirality is explained via the coupling between the dipole moment induced by the C-H bond around the chiral center and the magnetic dipole moment which is caused by the electronic current generated in the Raman process. Further analysis shows that the differential bond polarizabilities on the two opposite sides of the C-H bond around the chiral center are of opposite sign. This demonstrates the local asymmetry of this chiral molecule. The symmetric and antisymmetric coordinates are also analyzed, and their results are explained via the irreducible representations of C2 group.