The friction and wear behavior of micro-molybdenum disulfide (MoS2) is studied by atomic force microscope (AFM), and both positive and negative bias are applied to the conducive probe and substrate. The experimental results show that the nano-friction between MoS2 nano-sheets and AFM probes can be regulated by an external normal electric field. Friction force will increase with the increase of the external bias. The maximum bias has a threshold value. If the bias exceeds the threshold, it will promote the formation of MoS2 charge transfer and accelerate oxidation during the friction process. The tuning value of the friction force can be increased by 2 times, compared with the friction force under the condition of non-bias. We propose a feasible and valuable strategy to adjust the friction characteristics of the MoS2 system, which provides great significance to understand and control the nano-friction in the practical application.