The invention discloses a mining TBM (tunnel boring machine) water circulation system and a mining TBM water circulation method. The system comprises an external water source, an internal circulation water supply pipe, an internal circulation waterway, an internal circulation water outlet pipe and various mining TBM external devices. The external water source is connected with an inlet of the internal circulation water supply pipe, an outlet of the internal circulation water supply pipe is connected with an inlet of the internal circulation waterway, an outlet of the internal circulation waterway is connected with the internal circulation water outlet pipe, and an outlet of the internal circulation water outlet pipe is connected to a water inlet of each mining TBM external device. The external water source supplies water to an internal circulation tank and then distributes to each water pump; each water pump supplies water to the corresponding mining TBM internal device, and water is recycled after use and discharged to water supply pipes of the external devices to be used by the mining TBM external devices; water used by the mining TBM external devices is directly discharged to a roadway floor. Cooling effects of the water circulation system are greatly improved, water consumption and cooling requirements of the devices can be met, the operating rate of the devices is increased, and TMB quick efficient tunneling is guaranteed powerfully.