The microstructure, nano-indentation and friction properties of the CNx/SiC (carbon nitride/silicon carbon) bilayered films (SiC as interlayer), deposited on ultrafine-grained TiNi alloy substrate using magnetron sputtering technique at room temperature, were investigated. The results show that the CNx film is not fully compact with micro-pore defections in some zones, which has been possibly caused by the breaking off of inclusions in substrates. The CNx film presents high concentration graphite, low nano-hardness (5.23 GPa), low Young's modulus (33.29 Pa), but high hardness-to-modulus ratio (0.157). As sliding against Si3N4 (silicon nitride) balls (2 mm in radius), under ambient environment and 200 g load, the CNx film exhibits the friction coefficient of about 0.173 without film cracking and interface delaminating. On the other hand, under Kokubo simulation body fluid (SBF) and 500 g load, the CNx film exhibits the friction coefficient of about 0.103, but the interface delaminating occurs that is believed to be due to that the SBF enter into the film-film-substrate interfaces through micro-pores defections and corrode the interfaces