A catalyst in the form of a capsule catalyst was prepared by coating HZSM(5) membrane on a preshaped CO/SiO2 catalyst pellet. The capsule catalyst with HZSM(5) membrane exhibited excellent selectivity for light hydrocarbon synthesis, especially for isoparaffin synthesis from syngas (CO + H-2). Long-chain hydrocarbon formation was totally suppressed by the zeolite membrane. The modification of membrane and core catalyst significantly improved the catalytic properties of these new kinds of capsule catalysts.