This paper describes in-situ chemical vapor deposition (CVD) method to deposit alumna catalyst bed selectively on the suspended membrane of a microreactor. The microreactor with suspended membrane structure can realize good thermal isolation of the reaction area on the membrane, because heat conduction through the thin suspended membrane is quite small. However, it is difficult to form catalyst selectively on the suspended membrane. The solution can be given by the in-situ CVD method, by which alumina is deposited from alumina precursor selectively on the suspended membrane heated by integrated micro-heaters. We fabricated the suspended-membrane microreactors, and set up an in-situ CVD system using aluminum tri-isopropoxide (Al[(CH3) 2CHO]3) as the precursor. Preliminary deposition tests were preformed. The deposits were observed using a scanning electron microscope (SEM), and the composition of the deposits was analyzed by energy dispersive spectroscopy (EDX).