The invention discloses a method for treating and utilizing a mother solution containing sulfur produced by borax production of paigeite, which is characterized in that a borax mother solution containing the sulfur produced by using a CO2-soda method to process the paigeite for reaction to produce borax is divided into two parts for utilization according to the volume; the partial borax mother solution is transferred to a batching working section used for the production of the borax, and is used as a raw batching solution of a boric acid production process; then boron in the borax mother solution is transformed into a boric acid product to be separated through carbon decomposition, separation, evaporation and acidolysis working procedures of a boric acid production technology, and the obtained borax mother solution is further evaporated and salted out to ensure that the sulfur in the borax mother solution is transformed into a sodium sulfate byproduct to be separated; the remaining borax mother solution is returned to the batching working section used for the production of the borax, and is taken as the raw batching solution; and the content of sulfate is less than 0.2 percent calculated as SO4 in a finally obtained borax product. The clean production of zero emission of the borax mother solution and no sulfur pollution can be realized according to the method for treating and utilizing two parts of borax mother solutions.