The present invention provides a method for preparing rare earth Y-type molecular sieve, including the following steps: adopting conventional method to make NaY molecular sieve undergo rare-earth ionexchange treatment, filtering and feeding the obtained filter cake into roasting furnace, and roasting for 1-4 hr under the condition of 100% aqueous vapour atmosphere at 450-650 deg.C, then circularly returning 10-40% of roasted product into next batch of rare earth exchange slurry to continue the above-mentioned operation, and using the rest as REY molecular sieve product for preparing catalyst. Said invention adopts the process of "once exchange and once roasting", and can prepare the product which is identical to the REY molecular sieve made up by using conventional "twice exchange and twice roasting" process in properties and possesses better hydrothermal stability.