TiO

2

coating was prepared on biomedical Mg-Zn-Y-Nd alloys by DC magnetron sputtering.Effects of TiO

2

coating on the degradation rate and degradation behavior of magnesium alloys were investigated in Kokubo’s simulated body fluid（SBF）.The results show that the degradation rate of Mg-ZnY-Nd alloys is 1.39mm/y and 0.61mm/y

respectively

before and after surface modification treatment by the TiO

2

coating.The degradation uniformity of Mg-Zn-Y-Nd alloys is improved significantly as a result of the protection of TiO

2

coating.The change of TiO

2

coating after 24 himmersion in simulated body fluid is absent

and the Mg alloy substrate is not degraded in this period.Up to 72 himmersion

the TiO

2

coating is destroyed partly due to the generation of hydrogen and other degradation products

and the TiO

2

coating began to be peeled from substrate.Most of TiO

2

fragments can remain on the surface of substrate after 336 h

leading to a slower degradation of magnesium alloy.