To analyze the protection effect of the main drive seal lubrication system on the main drive bearing in terms of different working conditions, dynamic and static states, some suggestions for the design and use of the main drive of TBM are put forward. First, a transparent main drive seal grease diffusion device is developed, and the grease is injected through a grease metering valve. Different labyrinth lengths, labyrinth gaps, and lubrication quantities are set respectively, and the grease spreading arc length is measured to verify that the different grease diffusion and the main drive labyrinth designs have different protection effects on the main drive. Then, based on a simulation test platform of a main drive lubrication system, the different seal lubricant forms and lubricant quantities are combined with different cutterhead rotation speeds, the reasons for the temperature rise of the main drive seal are analyzed, and a suitable seal working temperature is recommended. Finally, the reasons for the seal failure of some TBM models are analyzed, and it is proposed that the lubrication system should be designed according to different TBM models to ensure good performance of the main drive seal system.