The invention relates to an adhesive for a building board and relates to the technical field of building materials. The adhesive for the building board is prepared from, by weight, 10-15 parts of phenolic resin, 5-15 parts of polyacrylate salt, 10-20 parts of talcum powder, 5-10 parts of chitosan, 5-15 parts of calcium carbonate, 5-20 parts of zinc oxide, 5-10 parts of propylene glycol methyl ether acetate, 10-20 parts of special organosilicone coupling agent, 10-30 parts of acetic ether, 5-10 parts of polyethylene glycol, 5-10 parts of ammonium chloride, 20-30 parts of ethyl orthosilicate, 5-10 parts of polyvinyl alcohol, 5-10 parts of ethylene propylene rubber, 5-10 part of nano rubber powder, and 5-20 parts of borax. The adhesive makes full use of the waste materials, achieves recycling of the waste materials, turns waste into treasure, saves the raw materials, and is an environment-friendly adhesive; the bonding property is good, the bonding strength is high, the water resistance is good, and the adhesive for the building board can be used for bonding of an adhesive-bonded board, a fiber board, metal, ceramics and glass materials.