The phase behavior of gas hydrate in reversed micellar solution without as well as with an enzyme were measured using propane and HCFC22 as gas species,and cytochrome c and alpha-chymotrypsin as enzymes. Equilibrium pressure without an enzyme decreased as the water to surfactant(AOT) ratio, W-0, decreased like the hydrate-formation from salt containing aqueous solution. After the hydrate was formed, the final value of W-0 were constant(W-0=3 similar to 4) independent of the initial W-0. By adding HCFC22 and also cooling the reversed micellar solution containing an enzyme and AOT, most of the free water in the pool of the micelle was converted to gas hydrate and caused the desolubilized enzyme to precipitate as a solid phase. Propane could form gas hydrate for the enzyme-containing micellar solution but not result in so much precipitation as HCFC22 because of the small solubility of propane in water. Finally we have proposed a new method for the recovery of enzyme from reversed micellar solution involving precipitation of the enzyme through formation of gas hydrate.