LiLSX molecular sieve

 The invention relates to a preparation method for a LiLSX molecular sieve, which comprises the steps that LSX zeolite is prepared, LSX is exchanged into KLSX, K2SO3 solution is adopted and KOH solution is used for regulating the PH value to 8.5, a method of displacing for a plurality of times is used with 2 minutes of replacing time for each replacement and the temperature of the solution is about 80 DEG C, exchange liquid after being exchanged a plurality times is used in the next group of the exchange process of K<+>; then a method that is similar to the replacement of K<+> solution is adopted to exchange into NH4LSX, the PH value of the solution is 8.5; then LiOH solution is used for exchanging Li<+> into LiLSX at the temperature of 50 DEG C and air is added to discharging NH3 at the same time; finally, washing, drying, etc. are carried out and finished products are obtained. The method is characterized by adopting ion exchange in a short time, using substances exchanged circularly and having suitable temperature and PH values of exchange solutions and high utilization ratio of Li, and finally the LiLSX molecular sieve with high degree of crystallinity is obtained.