The polymer-supported bimetallic catalyst system PVP-PdCl2-NiCl2/TPPTS/PPh3 has a good activity in the hydroxycarbonylation of styrene under aqueous-organic two-phase condition and can be reused four times with little loss of catalytic activity. The effects of temperature, CO pressure, and reaction time have been studied to obtain optimum reaction conditions. The experiments showed that the polymer could serve not only as a ligand but also as a surfactant. PPh3, the 'promoter ligand', was used in the catalyst system first to increase catalyst concentration close to the interface of the two phases, then to increase conversion and selectivity. (C) 2003 Elsevier B.V. All rights reserved.