Pure water and ultrapure water preparation device

The utility model provides a pure water and ultrapure water preparation device which comprises a pretreatment system and a reverse osmosis filter which are sequentially arranged along the flowing direction of sample water, an RO (reverse osmosis) membrane is arranged in the reverse osmosis filter, a sewage draining port of the reverse osmosis filter is communicated and connected with a sewage draining component, a water draining port of the reverse osmosis filter is communicated and connected with a sample discharging pipe, and the sample discharging pipe is communicated and connected with a water outlet of the reverse osmosis filter. A first resistivity sensor and a three-way electromagnetic valve are sequentially arranged on the sample discharging pipe in the flowing direction of sample water, one outlet of the three-way electromagnetic valve is communicated and connected with a pure water discharging pipe, the other outlet of the three-way electromagnetic valve is communicated and connected with an ultrapu