A method and a device for preparing a fluoride glass optical fiber preform by a tube suction method are provided. The method includes following steps: S1, heating and melting glass raw materials of outer cladding, inner cladding and a fiber core; S2, sucking to prepare the outer cladding; S3, sucking to prepare the inner cladding inside the outer cladding; S4, sucking to prepare the fiber core inside the inner cladding; and S5, annealing the outer cladding, the inner cladding and the fiber core to obtain a preform product.