Fe-Cr-Si-B-C alloy coatings were fabricated on 45 medium carbon steel by combination of a laser cladding and a mechanical vibration surface modification process. The microstructures, element distributions, phase compositions and microhardnesses of the Fe-Cr-Si-B-C cladding coatings were investigated by the X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) , Energy Disperse Spectroscopy (EDS) and the HVS-1000 hardness tester. The results show that the cladding coatings are mainly composed of α-(Fe, Cr)solid solution, M7C3(M=Fe, Cr)carbide, Fe2B boride and a small amount of Fe0.9Si0.1 compound. The microstructure of cladding coating interface transforms from a plane crystal to a banded structure and a columnar crystal under the mechanical vibration condition, and the grain refinement effect is the most obviousy when the amplitude is 0.13 -0.18 mm. Moreover, the enhanced phases in cladding coatings transform from the short rod to granular, lamellar and banded structures with the increase of vibration frequency, and the distribution patterns change from random distribution to dispersed and network distributions. Compared with the normal laser cladding coating, more less pores and cracks exist in the cladding coating under mechanical vibration condition, and the maximum microhardness increases by 13.9%. These results mean that the microstructures and distributions in the cladding coatings are influenced by a synergetic mechanism of amplitude and frequency.