A termite-controlling layer is formed with a particulate hardenable termite-controlling composition which comprises a hydraulic material, a soil and/or a termiticide, on an area to be treated. The soil may comprise a gravel component and a fine grain component, and the weight ratio of the gravel component relative to the fine grain component may be about 99.9/0.1 to 5/95. The fine grain component may comprise a sand component and a dirt component, and the weight ratio of the sand component relative to the dirt component may be about 99/1 to 10/90. The hardenable termite-controlling composition may further comprise a biocidal component, a deodorant component, or a humidity-conditioning component. In a termite-controlling process, the termite-controlling layer may be formed by laying the hardenable termite-controlling composition on the area to be treated, and applying at least a water to the laid hardenable termite-controlling composition. The use of the composition can effectively control termites in an underfloor area of a wooden building or a park.