The invention relates to a agricultural chemicals branch of technology, specifically to an agriculture chemicals effervescence composition and a preparation method thereof.The invention discloses an agricultural chemicals effervescence composition comprising effervescence components, active compounds of agricultural chemicals, and the invention is characterized in that, taking the total weight asthe basic reference, the agricultural chemicals effervescence composition also comprises the following components that water soluble base with a percentage by weight of 5-45% and water-soluble high molecular polymer with percentage by weight of 3-30% which form a united vector, and the active ingredients of agricultural chemicals are coated by the carrier to form a solid highly dispersed system.Every type of matters in the agricultural chemicals effervescence composition of the present invention has a better water-soluble performance, active compounds of agricultural chemicals can be highly dispersed into particles with a size of 0.001-0.1micrometre, the particle size of the active compounds of agricultural chemicals is much smaller than that of water-dispersion granulas, water dispersible powder and the like, the composition does not include any water-insoluble matters such as waterproofing agents, thinning agent and the like that are used by conventional effervescing agents, and once in water, the obtained effervescence composition is disintegrated instantly and rapidly and can be diffuse easily.Therefore, suspending particulate matters will never appear in the obtained solution, and if the prescription is reasonable, the solution will be clear and transparent; therefore, the composition can not only be used for expelling agriculture disease, but also be extensively used in the filed of expelling sanitation disease.