Ferrography has received much attention since it developed fifteen years ago as a new method of revealing wear debris in used lubricants. It has been proved that maintenance based on condition monitoring offers advantages of reduced loss of output, lower repair costs and increased safety due to a reduced frequency of unexpected failures.This paper presents the application of ferrography to the study of the effect of a particular factor on automobile bearing failure, in tests wear processes were monitored by ferrography. The forming laws of wear debris in wear processes are studied in detail. The test results show that wear debris analysis can be used to compare the effect of the variation of a particular factor on wear processes. The possibility of failure prevention and diagnosis of automobile mechanical elements by means of ferrography is also discussed here.