In this study, density functional theory in improved flat waves’ framework has been used. First of all, characterization, elastic and half-metallic properties of the CrSb-ZB compound at (GGA & LDA) and GGA + U approximation are calculated. The elastic calculations indicate that the CrSb-ZB is a ductile material. However, the calculation of Deby temperature indicates that the CrSb-ZB is meta-stable. The half-metallicity character is also preserved at CrSb/InP (001) interface by GGA + U. The conduction band minimum (CBM) of CrSb in the minority spin case lies about 1.26 eV above that of GaSb, suggesting that the major spin can be injected into GaSb without being flipped to the conduction bands of the minor spin.