The invention discloses a method for recycling
lithium salt and a
solvent in preparation of polyphenylene
sulfide. The method comprises the following operation processes: 1', washing a polyphenylene
sulfide product by use of an N-methyl pyrrolidone solution of which the percentage by weight of water is not larger than 50% at the temperature of 150 to 250 DEG C in an
inert gas environment, and combining the washing solution with a reaction medium solution; 2', transforming
sodium sulfide into
sodium chloride under the condition that the pH value of the combined solution is regulated to 6.5-7.0 in the
inert gas environment; 3', adding water into the solution transformed in the step 2 so that the low-molecular polyphenylene sulfide is precipitated and then separated; and 4', respectively separating and recycling the
sodium chloride, the N-methyl pyrrolidone and the
lithium chloride from the separated solution under the
inert gas environment. According to the method, the solvents need not to be evaporated out completely, so the
energy consumption is reduced greatly; the method can be performed in various intermittent or continuous ways and convenient and easy to implement, degradation caused because the
solvent is at high temperature for a long time is avoided, so the recycle rate of the
solvent is high, and the recycling quality is good; a separated and recycled polyphenylene sulfide
oligomer is utilizable, the purity of the recycled
lithium chloride is not lower than 98%, and the quality of the recycled sodium chloride is excellent.