A process for producing conjugated diene rubber and its composite includes polymerizing a conjugated diene or a conjugated diene and a vinyl aromatic hydrocarbon in a hydrocarbon solution by anionic polymerization to obtain conjugated diene rubber containing alkali metal in the polymer chain end reacting with at least one organic silane compound to become a modified conjugated diene rubber. After or during the modified conjugated diene rubber contacting with large amount of water, solvent and water content are removed from the modified conjugated diene by applicable hot sources, wherein coupling ratio of modified conjugated diene rubber is less than 40%, coupling ratio of modified conjugated diene rubber after contact with water is at least 50% The conjugated diene rubber and composite exhibit storage stability.