The present invention relates to cefazolin sodium pentahydrate crystal and a method for assembly and preparation of the crystal molecule. The cefazolin sodium pentahydrate crystal molecule contains five water molecules, orthorhombic system, space group of C222(1), in which sodium ion is bonded to the cefazolin molecule with a coordinate bond. The method for assembly and preparation of cefazolin sodium pentahydrate crystal molecule are: adding a solvent to a reactor equipped with a jacket, adding cefazolin acid and a sodium salt, heating until the reaction solution is clear, stirring continuously adjusting pH, upon the completion of the reaction, transferring the liquid into a jacketed crystallizer, adding crystal seeds or nucleating spontaneously, controlling cooling, slowly adding a antisolvent. The particle size of cefazolin sodium pentahydrate crystal according to the present invention is adjustable, and the distribution of particle size is concentrated, the product has good flowability, smooth surface, high crystallinity, good stability, and rapid dissolving rate.
