The utility model relates to a steam turbine bearing box oil supply unit, it is by power cord, switch, wire, switch, oil pipe, oil pump, oil tank, lubricating oil, filter screen, cooler, accumulator, liquid pump, coolant liquid, liquid bath, damage calorimeter, temperature detect switch, overflow valve, advance oil pipe, return oil pipe, the bearing box is constituteed, the bearing box is established into oil pipe, is returned oil pipe, advance oil pipe through the overflow device, decrease calorimeter, accumulator, oil pump and oil tank and communicate, return oil pipe and oil tank intercommunication, make lubricating oil circulate between bearing box and oil tank under the effect of oil pump, under the effect of overflow device, damage calorimeter, accumulator, make the lubricating oil in the bearing box item remain throughout in to set the temperature and pressure range.