Using a platform with an INV1612 multifunctional single disc flexible rotor, experimental research are performed to analyze the influences of the cleanliness degree and viscosity of lubricating oil on the working characteristics of a stable rotorbearing system. The influences were investigated through controlling the viscosity of lubricating oil and adding different quantities of pulverized coal to the types of lubricating oil. The results of research show that the overall vibration amplitude of the rotor increases with the decrease of the cleanliness degree and the enhancement of quantities of pulverized coal added. The increase of the kinematic viscosity and hyperthermal viscosity of lubricating oil enhances the lubricity, and the maximum amplitude of the rotor decreases. The hypothermal viscosity of lubricating oil has no significant influence on the amplitude of rotor. In addition, the relationship between the critical speed of rotor and the cleanliness of lubricating oil needs to be further studied.