A hot-dip galvannealed complex phase steel CP1000 was chosen, and different galvannealing parameters were adopted to get different Fe-Zn coatings on CP1000. Bending and tensile loadings were loaded on CP1000. Microstructure and fracture behaviors of the coatings were investigated using SEM. It was found that, with increasing galvannealing time,Zeta phase decreased on the surface of the coating, and more and more Delte phase was formed. Furthermore, with increasing galvannealing temperature, the formation velocity of Delte phase got faster. Bending tests showed that cracks could be found at the interface between the coating and CP1000, especially when galvannealing temperature was 550℃. Cracks in Delte phase, which were perpendicular to the interface, could also be found. Tensile tests showed that when the tensile strain was low enough, interface delamination did not happen. At the interface, when the galvannealing temperature was 510℃, cracks perpendicular to the interface could be found.