A new thermal insulation material made from rice straw (RSTIB) was developed using high frequency hot pressing. The goal of this study is to investigate the effect of high frequency heating, board density, particle size and ambient temperature on the properties of RSTIB. The results indicated that the optimum physical and mechanical properties of boards are obtained with a particle moisture content (MC) of 14%, a board density of 250 kg/m(3), and an L-type particle size. Additionally, the thermal insulation boards had fairly low thermal conductivity, ranging from 0.051 to 0.053 W/(mK). Comparison with conventional hot pressing confirmed that the pressing duration can be greatly shortened by high frequency hot pressing. The boards subjected to high frequency pressing had higher internal bonding strength (IB) values than the boards subjected to conventional hot pressing. As an environmentally friendly and renewable material, RSTIB is of interest for energy saving purposes when it is used as building insulation material for walls or ceilings. (C) 2014 Elsevier B.V. All rights reserved.