The invention provides an adhesive for the department of orthopaedics and a preparation method of the adhesive. The adhesive comprises the following components: silicate, phosphate, sodium alginate, magnesium oxide, calcium carbonate, kaolin, propylene glycol, glycerin, a retarder and deionized water. The preparation method comprises the following steps: weighing all the raw materials in parts by weight; performing ball-milling on silicate, phosphate, magnesium oxide, calcium carbonate and kaolin into powders, and uniformly mixing the five powders to obtain a mixture; sequentially adding sodium alginate, propylene glycol, glycerin and the retarder in the deionized water, uniformly stirring to obtain a settled solution, slowly adding the mixture in the settled solution under the condition of continuously stirring, and performing ultrasound at the room temperature to obtain the adhesive. The adhesive for the department of orthopaedics, prepared by the preparation method, is high in comprehensive performance, finally sets for about 60 minutes, has the compressive strength of 54.6-58.3 MPa, can meet the clinical application requirement, and is suitable for the treatment of osteoporosis and the fracture fixation and treatment in the department of orthopaedics and the spine surgery.