Silicoaluminophosphate（SAPO-5） molecular sieves were synthesized respectively by the piecewise and one-step crystalline methods,with metakaolin as the silicon and aluminum sources,phosphoric acid as the phosphorus source and with triethylamine combined with hexadecyl trimethyl ammonium bromide as the template agent.Then,the prepared molecular sieves were characterized by means of XRD,SEM,XPS and NH₃-TPD analysis.The results show that the product prepared by the piecewise crystalline method is of uniform pillar-like morphology,large size（about 20μm×5μm×5μm）,proper P∶Al∶Si molar ratio（1∶1.19∶0.67）,high Si content and higher total acid content（578.0μmol/g）,and that its initial activity（24.8%） is much higher than that of the product prepared by the one-step method（14.1%）.