A process for producing conjugated diene rubber, comprising: - polymerizing a conjugated diene or a conjugated diene and a vinyl aromatic hydrocarbon in a hydrocarbon solvent by anionic polymerization using an organic alkali metal compound to obtain alkali metal-containing conjugated diene rubber; - reacting the conjugated diene rubber containing the alkali metal in the polymer chain end with at least one organic silane compound to obtain a modified conjugated diene rubber, the organic silane compound comprising alkoxysilyl group compounds denoted by the following formula: wherein R 1 and R 2 are C 1 -C 12 alkyl group, C 6 -C 18 aromatic group, or allyl group, R 3 is C 1 -C 12 alkyl group or C 6 -C 18 aromatic group, R 4 is C 1 -C 12 alkoxy group, C 1 -C 12 alkyl group, C 6 -C 18 aromatic group or allyl group, and Y is oxygen- and/or nitrogen-containing functional groups; - contacting the modified conjugated diene rubber with water, wherein the weight ratio of water to solvent is at least 0.1; and - removing the solvent and water from the modified conjugated diene rubber by applying heat, after or during contacting the modified conjugated diene rubber with water; and - applying a storage test in 90 °C, 80 % relative humidity and 40 hours to the modified conjugated diene rubber, wherein the coupling ratio (C/R %) of the modified conjugated diene rubber is less than 40 %, the coupling ratio of the modified conjugated diene rubber after contact with water is at least 50 %, and the difference of Mooney viscosity between initial MVi (after water treatment) and MVs (after storage test in 90°C, 80 % relative humidity and 40 hours) is less than or equal to 10; wherein the coupling ratio refers to the ratio of polymers having a molecular weight which is higher than that of uncoupled polymers, relative to the weight of total polymers; and wherein the Mooney viscosity is measured under the conditions of 1 minute preheating and prolonged 4 minutes at 100° C, and the coupling ratio is measured with gel permeation chromatography equipped with refractive index detector, and tetrahydrofuran is acted as a mobile phase as performing measurement. - polymerizing a conjugated diene or a conjugated diene and a vinyl aromatic hydrocarbon in a hydrocarbon solvent by anionic polymerization using an organic alkali metal compound to obtain alkali metal-containing conjugated diene rubber; - reacting the conjugated diene rubber containing the alkali metal in the polymer chain end with at least one organic silane compound to obtain a modified conjugated diene rubber, the organic silane compound comprising alkoxysilyl group compounds denoted by the following formula: wherein R 1 and R 2 are C 1 -C 12 alkyl group, C 6 -C 18 aromatic group, or allyl group, R 3 is C 1 -C 12 alkyl group or C 6 -C 18 aromatic group, R 4 is C 1 -C 12 alkoxy group, C 1 -C 12 alkyl group, C 6 -C 18 aromatic group or allyl group, and Y is oxygen- and/or nitrogen-containing functional groups; R 1 and R 2 are C 1 -C 12 alkyl group, C 6 -C 18 aromatic group, or allyl group, R 3 is C 1 -C 12 alkyl group or C 6 -C 18 aromatic group, R 4 is C 1 -C 12 alkoxy group, C 1 -C 12 alkyl group, C 6 -C 18 aromatic group or allyl group, and Y is oxygen- and/or nitrogen-containing functional groups; - contacting the modified conjugated diene rubber with water, wherein the weight ratio of water to solvent is at least 0.1; and - removing the solvent and water from the modified conjugated diene rubber by applying heat, after or during contacting the modified conjugated diene rubber with water; and - applying a storage test in 90 °C, 80 % relative humidity and 40 hours to the modified conjugated diene rubber,