Preparation method of polycarbonate

The present invention relates to a method for preparing polycarbonate in a continuous manner. The method comprising: step A: mixing a bisphenol compound, an alkali metal hydroxide, and water to obtain a suspension containing an alkali metal salt hydrate solid of the bisphenol compound and an alkali metal hydroxide solution of the bisphenol compound, and separating the suspension to obtain an alkali metal salt hydrate of the bisphenol compound and an alkali metal hydroxide solution of the bisphenol compound; step B, mixing the alkali metal hydroxide solution of the bisphenol compound obtained in the step A with an inert organic solvent in which phosgene is dissolved, and carrying out reacting to obtain a reaction solution in which a polycarbonate oligomer is dissolved; and step C, mixing the reaction solution obtained in the step B with the alkali metal salt hydrate of the bisphenol compound obtained in the step A for a reaction, and adding an end-capping reagent and a catalyst to complete polycondensation rea