The invention relates to the field of nutrient solutions, in particular to a soilless vegetable culture nutrient solution and a preparation method. The soilless vegetable culture nutrient solution is prepared from sodium nitrate, urea phosphate, potassium nitrate, ammonium sulfate, magnesium chloride, Fe-EDTA, boric acid, manganese chloride, zinc sulfate, copper sulfate, sodium molybdate, mixed nitrogen-fixing bacterium solution and a nostoc extracting solution. The nutrient solution is simple and convenient to prepare, comprehensive in nutrient ingredient, high in biological activity and good in homogeneity, can decompose self-toxic materials produced by vegetables, remarkably improve the resistance, yield and the quality of the vegetables.