Reverse osmosis system and raw material water treatment method

The invention provides a reverse osmosis system and a raw material water treatment method. The reverse osmosis system comprises a softening resin module, a reverse osmosis part and a concentration part, wherein the softening resin module is used for performing ion replacement with raw material water to obtain first softened water. The reverse osmosis part is communicated with the softening resin module and is used for separating the first softened water into purified water and reverse osmosis concentrated water. The concentration part is communicated with the reverse osmosis part and the softening resin module and is used for separating the reverse osmosis concentrated water into second softened water and concentrated water. The second softened water can be conveyed to the reverse osmosis part to be separated again, so that the amount of purified water extracted from the raw material water is increased, and the utilization rate of the raw material water is increased; meanwhile, ions with relatively weak charg