The invention relates to a production method for an insulation board. The method comprises the following steps of: a, adding 50-70 parts by weight of expanded and vitrified small balls, 5-10 parts by weight of fibre glass, 5-20 parts by weight of silicon ash, 5-10 parts by weight of bentonite and 1-5 parts by weight of getter into a stirring kettle, then adding 2-5 parts by weight of wetting agent and 15-20 parts by weight of binding agent, and stirring the ingredients to obtain a pasty material; b, spreading out the well stirred pasty material on a microwave baking line, baking the pasty material until the water content of the board is less than 1% and then cutting the board into blocks; c, vacuumizing the board which is cut into blocks, wherein the degree of vacuum is below 200Pa; and d, cutting and packing the obtained insulation board. By utilizing the production method provided by the invention to produce the insulation board, the process is simple, no three wastes are discharged, and the produced insulation board can well achieve the effects of heat preservation and heat insulation, and has the combustion performance of grade A and the insulation thickness of 10-15mm; and the produced insulation board is light in weight and long in weather-proof time and has service life of more than 30 years.