The invention relates to sulfonylurea compound and metformin salts, a preparation method and application. The preparation method comprises the following steps: dissolving a sulfonylurea compound and metformin into a solvent according to a mole ratio of (1:0.9):(1:1.1) so as to obtain a mixture; performing reaction crystallization on the mixture under a condition of 25-50 DEG C for 12-48 hours; andperforming solid-liquid phase separation on the obtained product, and performing drying, so as to obtain a salt type solid product. The sulfonylurea compound is gliquidone or glibenclamide. The gliquidone-metformin salt and the glibenclamide-metformin salt provided by the invention are applied to medicines for preventing and treating diabetes. The wet absorption capacities of the salt type products provided by the invention are greatly increased when being compared with that of metformin, that is, the hygroscopy gain of the metformin is 35% when the relative humidity is 75%, and the hygroscopy gains of the salt type products are smaller than 1%; and the dissolubility of the salt type products is greatly improved when being compared with that of the sulfonylurea compound, that is, the dissolubility of the sulfonylurea compound in water is smaller than 0.03mg/ml, and the dissolubility after salt formation is 10.61mg/ml and 16.78mg/ml respectively.