Abstract: The diatomite was used as wrapping reagent and tetraethyl orthosilicate as adhesive to link layers of diatomite,and thus the compound fertilizer of diatomite coated nitrogenous,potassium and phosphate fertilizers were prepared in different dispersants.The characterization of functional groups of the samples were performed with Infrared spectrum.The controlled release property was tested by means of drop-leaching experiment. The results showed that the diatomite exhibited slowly releasing effect for the soluble N and K fertilizers. However,the diatomite promoted the release of insoluble P fertilizer. The effect of controlled release N and K fertilizers was good with the tetraethyl orthosilicate as binder.