In order to clarify the effects of reactive element Y on the properties of Si-B co-deposition coating on Mo substrate,the Si-B-Y_2O_3 and Si-B-Y co-deposition coatings were prepared at 1300°C for 5 h by using the pack mixtures 16Si-4B-xY_2O_3/Y-4NaF-(76–x)Al_2O_3(wt.%,x=0,0.5,1,2,4,8).X-ray diffraction(XRD),energy dispersive spectroscopy(EDS) and wavelength dispersive spectroscopy(WDS) techniques were used to analyze the structure and oxidation behavior of these coatings.The results revealed that the Si-B-Y_2O_3 and Si-B-Y co-deposition coatings had the same structure with that of the Si-B co-deposition coating.However,Y was incorporated into these coatings and the thicknesses of these coatings were thicker than that of the Si-B co-deposition coating.In addition,the Si-B-Y co-deposition coating demonstrated better cyclic oxidation resistance than the Si-B co-deposition coating at 1100 °C.The modifying mechanism of Y on the Si-B co-deposition coating was discussed. In order to clarify the effects of reactive element Y on the properties of Si-B co-deposition coating on Mo substrate, the Si-B-Y_2O_3 and Si-BY co-deposition coatings were prepared at 1300 ° C for 5 h by using the pack mixtures 16Si-4B-xY 2 O 3 / Y-4NaF- (76-x) Al 2 O 3 (wt.%, x = 0,0.5,1,2,4,8). X-ray diffraction (XRD) (EDS) and wavelength dispersive spectroscopy (WDS) techniques were used to analyze the structure and oxidation behavior of these coatings. The results revealed that the Si-B-Y_2O_3 and Si-BY co-deposition coatings had the same structure with that of the Si-B co-deposition coating. Even, Y was incorporated into these coatings and the thicknesses of these coatings were thicker than that of the Si-B co-deposition coating. In addition, the Si-BY co-deposition coating characterized better cyclic oxidation resistance than the Si-B co-deposition coating at 1100 ° C. The modifying mechanism of Y on the Si-B co-deposition coating was discussed.