The invention discloses a temperature-controlled liquid swellable rubber, which contains (by weight), polyether glycol 30 to 60 percent, toluene diisocyanate 5 to 40 percent, unsaturated resin 2 to 30 percent, phenol-formaldehyde resin 2 to 30 percent, natural rubber 2 to 20 percent, catalyst 0.01 to 3 percent, reaction temperature controlling agent 5 to 40 percent, solvent 2 to 30 percent, plasticizer 2 to 10 percent, thermal stabilizer 0.5 to 2 percent, and foam regulator 0.5 to 2 percent. The preparation method comprises the following steps: adding polyether glycol into a reaction kettle at the weight percentage of 30 to 60 percent, heating to 120 DEG C, dehydrating for 30 min, cooling to 45 DEG C, adding toluene diisocyanate 5 to 40 percent, heating to 80 DEG C to 95 DEG C, keeping the temperature for 1.5 to 4 hr, cooling to 45 DEG C, adding the solvent 2 to 30 percent, adding reaction temperature controlling agent 5 to 40 percent and catalyst 0.01 to 3 percent into the reaction kettle, heating to a reaction control temperature 60 to 95 DEG C, keeping the temperature for 4 to 8hr, cooling to 45 DEG C, adding the plasticizer 2 to 10 percent, unsaturated resin 2 to 30 percent, phenol-formaldehyde resin 2 to 30 percent, natural rubber 2 to 20 percent, thermal stabilizer 0.5 to 2 percent, and foam regulator 0.5 to 2 percent, stirring for 0.5 to 1 hr, discharging, and packagingto obtain the product.