The invention discloses a preparation method of an SAPO series molecular sieve membrane with a metal oxide as a carrier. The preparation method disclosed by the invention is a diauxic growth preparation method for preparing an SAPO series molecular sieve on the surface of the metal oxide by adopting a method of pre-spraying crystal seeds. The preparation method comprises the following steps: firstly pre-coating a gel layer on the surface of the metal oxide, wherein the gel layer can effectively inhibit dissolution or melting of the metal oxide during the crystallization process; further dispersing the crystal seeds in ethanol to form a suspension, coating the suspension on the surface of the metal oxide after pretreatment, and drying to get a crystal seed layer; and placing the metal oxide coated with the crystal seed layer into synthetic fluid and crystallizing at the temperature of 170-230 DEG C to get the continuous and compact SAPO series molecular sieve membrane. According to the preparation method disclosed by the invention, the SAPO series molecular sieve with a special pore canal structure and catalytic performance and the metal oxide with the better catalytic performance can be combined to form a catalytic membrane reactor, and the preparation method further has good application potential in the fields of catalysis and separation.