Objective: In this paper, we study the metal to metal artificial joint wear form of cobalt (Co) nanoparticles on TCMK 1 cells to produce biological effect, at the same time ,for the first time application of antioxidant n-acetyl cysteine (NAC) reduce the biological effect by cobalt (Co) nanoparticles on renal tubular epithelial cells (TCMK - 1). To further explore protein expression in the process of cell apoptosis and cell autophagy, this is the first report that describes CoNPS-induced cytotoxicity inTCMK-1cells attenuated by antioxidative agents NAC, inhibition of cell death, ROS-related signaling and cytokine expression Methods: TCMK-1cells were treated with Co NPs and NAC in different concentrations and time. Then cells were examined morphologically and evaluate the cytotoxicity by different NPs and NAC with CCK-8,WB analysis, Apoptosis detection. Results: Under certain conditions, CoNPs in different constituent ratio showed cytotoxicity in a concentration and time- dependent manner, in addition, CoNPS activated the MAPK pathways thereby increasing p-ERK,p-p38 and p-JNK production. All of these stimulation phenomena could be inhibited by NAC in vitro study. Conclusions: 1. CoNPS could reduce the activity of TCMK - 1 cells,at the same time,it has a concentration and time- dependent effect. 2. CoNPS could increase the number of apoptosis in TCMK-1 cells, protein expression increased apoptosis signaling pathways. 3. NAC may prevent the development of CoNPS-induced cytotoxicity by inhibiting of ROS-induced cell death and cytokine expression.