The invention relates to the technical field of vegetable planting, and particularly discloses a plant fermentation extract for improving vegetable soil planting and a preparation method thereof. Theplant fermentation extract for improving vegetable soil planting is prepared from cape jasmine, cyrtomium fortunei, germs, tricholoma matsutake, salicornia europaea, honeysuckle, dried lumbricus, pericarpium citri reticulatae, zinc-rich yeast, hirudin, eucommia ulmoides, selenium yeast, seaweed, red ginseng, monopotassium phosphate, fructus aurantii immaturus, cordyceps sinensis, magnesium sulfate, shredded coconut stuffing, liquorice, adenophora root and pollen through fermentation, extraction and pulverization. Raw materials are easy to obtain, the preparation process is simple, the soil structure is effectively improved, the number and activity of effective microorganisms in soil are increased, the soil magnesium content is increased, vegetable growth, yield increase and quality improvement are facilitated, and the plant fermentation extract is suitable for wide application and popularization.