The invention discloses an instant adhesive. The instant adhesive is prepared from the following raw materials: polymethyl methacrylate, ethyl cyanoacetate, 30-35% formaldehyde, piperidine, dichloroethane, a hydroquinone polymerization inhibitor and modified sepiolite. The instant adhesive is prepared by the following steps of: based on parts by weight, mixing the polymethyl methacrylate, the piperidine, the ethyl cyanoacetate and the 35% formaldehyde and then adding the obtained mixture into a reaction kettle to react for 1 hour at 70 DEG C when heated; and then adding the hydroquinone polymerization inhibitor, the modified sepiolite and the dichloroethane for reduced pressure distillation at 180 DEG C. The instant adhesive disclosed by the invention is an adhesive which has single component and is instantly cured on meeting moisture, and is convenient to use, the adhered surface needs no special pretreatment, heating and pressurizing are not necessary, and the adhesive is widely applied to the adhesion and location between plastics, and between the plastic and metal, is water-fast, cannot be combusted, is good in low-temperature adhesion property, and is low in cost.