The invention relates to a preparation method of crystalline rare-earth 
carbonate. According to the scheme, the method comprises the following steps: selecting 
ion absorpt deposit and carrying out an in-situ leaching method, wherein the in-situ leaching method comprises the following steps: preparing a mixed leaching agent with the 
mass fraction being 2% by using two 
ammonium salts which are in a 
mass ratio of (1-4) to 1, adding an aluminum inhibitor which is 0.05% of 
mass of the mixed leaching agent, stirring evenly, and then carrying out in-situ leaching according to a liquid-
solid ratio of (0.1-2) to 1; after the leaching solution completely seeps, adding top wash ore which is 10% of mass of the leaching agent, collecting the leaching solution, clarifying, and adding a precipitator, wherein the 
mass ratio of the precipitator to the leaching solution is (0.1-0.5) to 1; fully stirring for over 30 minutes, and standing and 
ageing for 6-24hours; filtering, washing 
sediment twice with clear water, filtering again, and baking at 110 DEG C, so as to obtain the crystalline rare-earth 
carbonate, wherein the 
recovery rate is 70-85%, and the purity is 90-95%. The crystalline rare-earth 
carbonate is prepared from easily available raw materials and is low in cost, high in 
recovery rate and high in product purity.