Abstract: CeAPO-5 molecular sieves were synthesized in the absent of HF using hydrothermal method. The effect of synthesis conditions including gel process, the kinds of Al resource and template, and the adding amounts of template, CeO2, and H2O on the structure of CeAPO-5 molecular sieves was investigated by X-ray fluorescence spectrometry, N2 adsorption-desorption, XRD, and NMR of 27Al. When the Al resource is added into phosphoric acid aqueous solution under the synthesis conditions of V250 powder as an Al resource, triethylamine (Et3N) as a template, and n(Al2O3)/n(P2O5)=0.98, n(Et3N)/n(P2O5)=2.0, n(CeO2)/n(P2O5)=0.06, n(H2O)/n(P2O5)=50, the relative crystallinity of CeAPO-5 molecular sieve reaches 99.4%