Composition capable of increasing wheat yield, method of preparing composition and application of composition

The invention discloses a composition capable of increasing wheat yield, which includes, by weight, 15%-18% of betaine, 0.08%-0.12% of triacontanol, 3%-4% of emulsifier, 10%-12% of dispersing-spreading agent, and the balance of water. The method of preparing the composition includes: A, preparing triacontanol emulsion; firstly, adding water in a reactor, sequentially adding triacontanol crystal and the emulsifier, heating to 80-90 DEG C, shearing and stirring at high speed for 20-30 minutes, and cooling to below 45 DEG C to obtain the triacontanol emulsion; and B, adding the betaine, the dispersing-spreading agent and water into the triacontanol emulsion obtained in the former step, and shearing and stirring at high speed for 20-30 minutes to obtain the composition. By means of the composition, photosynthetic efficiency of wheat can be increased, and further, salt resistance, cold resistance, drought resistance and dry-hot wind resistance of plants can be improved while the effects are stable.