Damage often occurs to the main bearings of TBMs during tunnel construction, which often results in serious consequences. Instead of the quality of the main bearing itself, personal factors are always the main factors for the damage of the main bearings. In the paper, the malfunction of the main bearing of TB880E TBM used in the construction of Zhongtianshan tunnel on the second railway line from Turpan to Korla in south Xinjiang, China are presented, the countermeasures for the malfunctions and the application of the main bearing state monitoring technology are provided, the causes for and the consequences of the malfunctions of the main bearing are analyzed in terms of assembly, commissioning, operation, maintenance, repairing and malfunction treatment, and suggestions are made on the assembly, commissioning, operation and maintenance of the main bearing, so as to minimize the main bearing damage incidents.