In phosphate–citric acid buffer (pH = 8.0) containing sodium dodecylbenzenesulfonate (SDBS) as a surfactant, enzymatic polymerization of phenol catalyzed by horseradish peroxidase (HRP) is efficiently performed. The as-synthesized phenol polymer is completely soluble in organic solvents such as dimethylfomamide, dimethylsulfoxide, acetone and tetrahydrofuran. The aqueous micelle system provides a new environmentally friendly method for HRP-catalyzed phenol polymerization. The effects of the dosage of SDBS and reaction temperature on the yield of the target phenol polymer are investigated. The soluble phenol polymer is composed of phenylene and oxyphenylene units as determined using infrared and 1 H NMR spectral analyses. The number-average molecular weight calculated from gel permeation chromatography (GPC) is in the range 900–1500 g mol−1 and the dispersity in the range 3.4–6.3. In all cases, the values of weight-average molecular weight characterized using GPC–static light scattering are tens of thousands. It is concluded that a branched structure is produced in the aqueous micelle system. The phenol polymer prepared possesses good thermal stability for it is completely decomposed at a temperature as high as 628 °C in air.