The invention belongs to the field of agricultural production and discloses a sugar alcohol calcium magnesium zinc boron compound liquid fertilizer and a preparation method and application thereof. The liquid fertilizer is prepared from various mother solutions, a chelating agent, a plant growth regulator and surface active materials. The preparation method comprises the following steps: causing sugar alcohol to respectively react with calcium salt, magnesium salt, zinc salt and boric acid to prepare calcium, magnesium, zinc and boron mother solutions, then mixing the mother solutions according to a certain ratio, and adding the chelating agent to cause the mother solutions to carry out secondary chelating reaction; after a while, adding the plant growth regulator and the surface active materials into reaction liquid, uniformly mixing, and cooling to the room temperature to obtain the high-concentration, stable and good-effect compound liquid fertilizer. The prepared liquid fertilizer provides adequate calcium, magnesium, zinc and boron and other nutrients for plants and can also carry out mixing of different elements and proportions according to the needs of different plants and different growth stages of plants.