The invention relates to a complex-formulation vegetation adjusting composition containing allantoin, which is the vegetation adjusting composition containing an effective active component A and an effective active component B. The active component A is allantoin, the active component B is selected from any compound of ethephon, paclobutrazol, uniconazole, tetramethyl glutaric aciduria, naphthylacetic acid, compound sodium nitrophenolate and choline chloride, which are used for enhancing enzyme activity, promoting seed germination, increasing germination capacity, enhancing photosynthetic intensity, increasing chlorophyll content, protecting green color and resisting aging, promoting roots development, promoting effective absorption of the fertilizers by crops, helping good growth for inferior position of the crops, enhancing water and the fertilizer absorption by the plants, adjusting the moisture balance in the plants, increasing the drought resistance and cold resistance of the plants, increasing immunity, enhancing disease and insect resistance, improving crops quality, and increasing yield and income.