A liquid type special cucumber composite foliage fertilizer takes water as solvent and comprises macro, medium and micro nutrients and assistants. The content of the macro nutrient (N+P2O5+K2O) is larger than 70g/L, and the mass ratio is that N:P2O5:K2O equals to (4-6):1:(6-8); the content of the medium nutrient (Mg+S) is larger than 20g/L, and the mass ratio is that Mg:S equals to 1:(2.0-3.0); the content of the micro nutrient (Zn+Mn+B+Mo+Fe) is larger than 10g/L, and the mass ratio is that Zn:B:Fe:Mn:Mo equals to (4-5):(3-4):(2-3):(1-2):1; the chelating agent content is 5 to 35g/l, and the wetting agent content is 0.05 to 0.3g/L. When being used, the special cucumber composite foliage fertilizer is diluted with water with a ratio of 1:(500-800), and the dilution liquid for each mu is 100 to 150 kg and is sprayed at the middle and upper parts of the leaves, particularly the backs of leaves. The foliage fertilizer is sprayed before flowering of cucumber, once for each seven days and totally three times, and in the results period, twice spray is needed with a time interval of seven to ten days, and the average yield increase rate can reach above 15%.