Disclosed is a process for preparing superfine silica and nano-alumina by utilizing kaolin as raw materials. In the method, the kaolin is calcined, lixiviated and filtered, filter liquor containing silicon dioxide and a filter cake containing aluminum trichloride are obtained, then, the filter liquor and the filter cake are removed by impurity and post-treated, and finally the final product of the powder of the nano-alumina and the powder of the superfine silica are obtained. The process can prepare the superfine silica and the nano-alumina simultaneously, thereby achieving the comprehensive application of the kaolin, and the prepared two products are fine in product index and high in added value of products.