Poor lubrication includes improper lubricant selection, improper filling amount or oil level of grease, deterioration of oil (grease) or lack of oil (grease).1) The selection of lubricant and lubrication method are unreasonableThe rolling bearing of vertical roller mill lubricant shall be selected according to the bearing operating temperature, speed index, load characteristics, lubrication mode and other factors. If the lubricant is improperly selected and the viscosity is too low or too high, it is difficult to form oil film, which will make the heat generated during bearing operation unable to be taken away and cause bearing heating.2) Improper amount of oil (grease)Too little or too much oil (grease) will cause fever due to lack of oil or too much oil and large stirring.3) Failure to change oil on time, deterioration of lubricating oil and impurities such as iron filings in lubricating oil lead to deterioration of lubrication condition.4) The bearing is short of oil, hot and invalid due to oil leakage of vertical roller mill bearing seat and other reasons.