A salt spray resistant structure of fan motor assembly includes a silicon steel sheet assembly, an insulation support assembly and an encapsulation layer. An inner side of the silicon steel sheet assembly defines a connection hole. A winding assembly is wound on the silicon steel sheet assembly and electrically connected with a circuit board. A first extension section protrudes from the silicon steel sheet assembly into the connection hole to cover a part of the inner side. A bearing cup covers the other part of the inner side. The encapsulation layer encapsulates the insulation support assembly, the winding assembly, the silicon steel sheet assembly and the circuit board so as to achieve salt spray resistant effect.