Ti-50.6 at.% Ni shape memory alloy was coated with tantalum using multi arc ion-plating technique with the aim to increase its radiopacity and biocompatibility. The surface characteristics were investigated by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The results of XPS survey spectra show that a thin oxide film are formed inside tantalum coating as a result of natural passivation of Ta in atmosphere. The hemocompatibility was evaluated in vitro by clotting time and platelet adhesion measurement. The results of our study showed that the clotting time of tantalum was higher than that of the TiNi alloys and no sign of accumulation and only slight pseudopodium was observed on the tantalum coatings, suggesting that the tantalum coatings can improve the biocompatibility of TiNi alloy.