Ultrapure water preparation system and adblue preparation method

The invention relates to an ultrapure water preparation system and an adblue preparation method. The ultrapure water preparation system comprises a front filter, a first-stage filter device, a second-stage filter device, a third-stage filter device and an EDI ultrapure water module which are sequentially connected. The filter-stage filter device comprises an ultra-filtration assembly. The second-stage filter device comprises a reverse osmosis membrane assembly. The third-stage filter device comprises a precise filter. The ultrapure water preparation system is provided with the filter devices of multiple stages, the filter devices of the multiple stages are reasonable in arrangement, ultrapure water prepared through the ultrapure water preparation system is free of impurities, bacteria, viruses, organic matter and other pollution ions, the water quality electrical resistivity reaches more than 15 megohm, the water quality meets the requirements for all technical indexes of a urea solution, and ultrapure water can be unceasingly prepared on site according to the output capacity requirement of an adblue solution.