Besides metal ions, the clays in lime concretion fluvioaquic soil (Shajiang black soil) can be also reacted with humic substance of weathered coal. The degree of organo-mineral complexation between lime concretion fluvio-aquic soil and weathered coal was about 84%. The more the weathered coal added, the lower the degree of complexaition was. The adsorption ability by soil for weathered coal may be expressed by the organic matter content in heavy fraction of soil, or by the organic matter content times the heavy fraction content. The experiment also showed that four factors, i.e. pH, the amount of Al(OH)₃ added, the times of alternate drying and wettiah and the amount of weathered coal added, could influence the adsorption of weathered coal by soil clay, but the last one was the dominant. The loosely combined humus was the main part of organic matter of weathered coal adsorbed by lime concretion fluvio-aquic soil. Its amount adsorbed was also influenced by the pH of the system. The loosely combined humus in heavy fraction wd organic matter in the fraction <2 μm of soil were directly proportional to the amount of organic. matter. in heavy fraction of soil.