In this article, NiCrAlY bond coatings was deposited on the Ni-based superalloy (N5) by EB-PVD, and the sample was oxidized by the constant temperature of 1000℃ for different time. Interdiffusion behavior of interface between subatrate and bond coat, as well as, the foramation mechanism of reaction zone was analyaed by SEM、EDS and XRD. The result shows that the elements of Al and Cr in the NiCrAlY coating was diffused to the N5 substrate and formed an interdiffusion reaction zone dominated with β-NiAl phase and α-Cr phase; and the Ni elements in the N5 substrate was diffused to the NiCrAlY coatings, forming the secondary reaction zone and TCP phase, which was mainly composed with the γ’-Ni₃Al and refractory metal respectively.