Lead-Bismuth Eutectic (LBE) is an interesting candidate as a coolant for Generation IV nuclear power plants. Lead-bismuth lubricated radial guide bearing is the key component of the mechanical pump in a lead-bismuth coolant system. In this paper, the transient calculation model of multiphase lubrication flow field of journal bearing is established by using Singhal full cavitation model and structured dynamic grid technique. Due to the saturated vapors of LBE being very low, the effects of different Non-Condensable Gas (NCG) contents on the characteristics of lead-bismuth lubricated journal bearing systems were analyzed. The results show that the NCG content has an obvious influence on the working state of the bearing. With the increase in NCG content, the bearing load capacity decreases. Under the same load, with the increase in NCG content, the eccentricity of the static equilibrium position will be larger, which will increase the risk of bearing contact with the bearing bush. Moreover, the increase of NCG content will lead to the increase of tangential oil film force work, which is helpful to improve rotor stability.