The invention relates to the technical field of soil improvement and in particular relates to an attapulgite soil improvement agent and a preparation method. The improvement agent is prepared from the following components: modified attapulgite, plant straw, furnace slag, animal dung, potassium fulvate, radix sanguisorbae, herba polygoni salicifolii, rhizoma acori tatarinowii, camphor tree leaves, green bristlegrass herb, tobacco, folium artemisiae argyi and strains. The preparation method comprises the following steps: weighing the plant straw and Chinese medicinal herb components and crushing; putting the materials into a fermentation tank; adding the modified attapulgite, the animal dung, the furnace slag and the potassium fulvate and uniformly stirring; adding the fermentation strains and a proper amount of water for fermenting; after fermenting for 5 days, carrying out turning treatment on a fermented product and continually fermenting for 7 days; after fermenting, drying to obtain the attapulgite soil improvement agent. The improvement agent provided by the invention can be used for effectively adjusting a soil structure and providing necessary microelements for soil, and can also be used for effectively killing insects in the soil; the preparation method is simple and convenient to operate and has relatively good application value.