The invention relates to a method for preparing polycarbonate. The method utilizes an interface method, and comprises the steps of: mixing alkaline aqueous solution of one or more dihydroxy aromatic hydrocarbons and organic solution of carbonyl chloride(phosgene); controlling the pH value to be between 9 and 12.5 in the whole process; and performing an interfacial polymerization reaction of a phenol chain terminator, the dihydroxy aromatic hydrocarbons and the phosgene in the presence of a catalyst, namely an amphiphilic block copolymer to prepare the polycarbonate. The method utilizes the amphiphilic block copolymer as the catalyst for preparing the polycarbonate by the interface method, which can increase the utilization rate of the carbonyl chloride, reduce the consumption of the carbonyl chloride, and improve the utilization rate of bisphenol; the catalyst can promote the rapid transformation of chloroformate and obtain a polycarbonate product with low inclusion amount of dihydroxy aromatic compounds; and no phenol precipitations are precipitated after a wastewater phase is acidified, and a catalyst material can be treated and recovered by adopting a conventional method.