The invention relates to a preparation method of a halophyte mixed silage feed, and belongs to the field of feed production. The preparation method comprises the following steps: firstly, crushing halophyte such as alicornia, by gas streams, blanking the crushed halophyte, stirring the blanked halophyte, selecting 90% of the stirred halophyte for natural air drying, and forming halophyte fibers; in addition, enabling 10% of the halophyte to form halophyte mixed serosity; then, crushing waste, such as corn straws, and blanking the crushed waste to obtain the blanked waste to be used as fermentation raw materials; spraying a diluent EM probiotics stock solution in a fermentation case, enabling silage raw materials to be loaded in the fermentation case, when the height of the silage raw materials loaded in the fermentation case achieves 9cm of the height of the fermentation case, loading the halophyte fibers on the silage raw materials to be 1cm above the height of the silage raw materials, circularly performing the operations of loading the silage raw materials and the halophyte fibers, spraying the diluent EM probiotics stock solution, adopting a polyethylene film for sealing package until the fermentation case is loaded fully by parity of reasoning; and finally, compacting the silage raw materials and the halophyte fibers, spraying the diluent EM probiotics stock solution and halophyte mixed serosity, covering the polyethylene film, and performing sealed fermentation. The preparation method disclosed by the invention has the benefits that the nutrition of the silage feed is maintained not to be lost, the mouth feel of the feed is improved, the operation steps are simple, and the cost is low.