The invention provides a plant nutrient solution for soilless culture of tomato. The plant nutrient solution is prepared by the following raw materials in part by weight: 2 to 4 parts of potassium nitrate, 3 to 8 parts of calcium nitrate, 1 to 5 parts of magnesium sulfate, 1 to 3 parts of potassium phosphate, 1 to 2 parts of potassium sulphate, 1 to 2 parts of monopotassium phosphate, 0.1 to 0.15 part of Na2-EDTA, 0.05 to 0.1 part of Fe-EDTA, 0.01 to 0.05 part of molybdic acid, 0.01 to 0.03 part of manganese sulfate, 0.3 to 0.5 part of sodium tetraborate, 2 to 4 parts of superphosphate, 0.003 to 0.01 part of zinc sulfate, 0.001 to 0.002 part of copper sulfate, 0.001 to 0.003 part of ammonium nitrate, 1 to 3 parts of urea, 1 to 2 parts of organic acid, 0.5 to 1 part of beta cyclodextrin, 0.05 to 0.1 part of vitamin B, 2 to 4 parts of chitosan, 1 to 2 parts of nicotinamide, 0.5 to 2 parts of amino acid, 0.3 to 0.5 part of diethyl aminoethyl hexanoate, 0.02 to 0.5 part of gibberellin, and 5,000 to 7,000 parts of water. According to experiment, the plant nutrient solution provided by the invention can be used for carrying out soilless culture of tomato, and the tomato has high plant height, thick stem, high cluster and high output.