1 continuous operation, stable quality of product water 2 without using regenerated 3 not for regeneration and downtime 4 saves the recoil and cleaning water 5 with high yield to produce ultrapure water ( yield can reach as high as 95% ) 6 no sewage, without sewage treatment facilities 7 without acid-base reserve and acid-base dilute transport facilities 8 decreases the workshop building area 9 the use of safe and reliable, avoiding exposure of workers to reduce the operation cost and repair pH 10 11 easy installation, low installation cost of reverse osmosis equipment system desalting rate is generally 98-99%. the desalting rate in most situations is to meet the requirements. In the electronics industry, super high pressure boiler water supply, individual pharmaceutical industry on water requirement may be higher. This single stage reverse osmosis equipment can not meet the requirements. The following method can be further purified by reverse osmosis water to meet the requirements of 1: two-stage reverse osmosis: single stage reverse osmosis pure water for a reverse osmosis treatment to improve water purity. 2: reverse osmosis and ion-exchange combination can use a smaller plant, lower operating costs to produce ultrapure water. 3: reverse osmosis and ion-exchange binding can be reduced using the factory area and low operating costs.