This research aims to study the application of coconut meal and corncob fiber as high density cement-bonded fiberboard. The cement: fine sand: coconut meal and corncob fiber: water ratio is equal to 1: 0.2: 0.05: 0.3. The fibers are taken from coconut meal and corncob that 5 ratios are used to all of fiber mixing. The fiberboard production use casting in normal temperature. Resulting the CN75 ratio (coconut meal and corncob fiber is equal to 0.0125: 0.0375) is suitable ratio which pass TIS 878- 2537 standard (cement bonded particle board) and has good physicalproperties mechanical properties and thermal insulation.